Air qual. epa

1. federal register Wednesday August 4, 1999 Part III Environmental Protection Agency 40 CFR Part 58 Air Quality Index Reporting; Final Rule

2. 42530 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and RegulationsENVIRONMENTAL PROTECTION FOR FURTHER INFORMATION CONTACT: 214–4897, or sent by e-mail toAGENCY Terence Fitz-Simons, EPA (MD–14), ball.michael@epa.gov. Research Triangle Park, NC 27711, (1) Community Action Programs:40 CFR Part 58 telephone (919) 541–0889, e-mail fitz- Blueprint for Program Design (EPA 420– simons.terence@epa.gov. For health R–98–003).[FRL–6409–7] effects information, contact Susan Lyon Table of Contents Stone, EPA (MD–15), Research TriangleRIN 2060–AH92 I. Background Park, NC 27711, telephone (919) 541– 1146, e-mail stone.susan@epa.gov. A. What Are the Legislative Requirements?Air Quality Index Reporting B. What Is the History of the Air Quality SUPPLEMENTARY INFORMATION: InAGENCY: Environmental Protection Index? compliance with President Clinton’s C. What Programs Are Related to the AQI?Agency (EPA). June 1, 1998 Executive Memorandum on 1. Ozone and Particulate Matter NAAQSACTION: Final rule. Plain Language in government writing, Revisions this package is written using plain 2. Real-Time Data Reporting InitiativeSUMMARY: Today, EPA adopts revisions language. Thus, the use of ‘‘we’’ or ‘‘us’’ (Ozone Mapping Project)to the uniform air quality index used by in this package refers to EPA. The use 3. Community Action ProgramsStates for daily air quality reporting to of ‘‘you’’ refers to the reader and may II. Rationale for Final Revisionsthe general public in accordance with include industry, State and local A. What Revisions Did We Propose?section 319 of the Clean Air Act (Act). agencies, environmental groups and 1. What Were the Proposed GeneralThese changes include the addition of Changes? other interested individuals. 2. What Were the Proposed Changes to thethe following elements: a new category Availability of Related Information Sub-Indices?described as ‘‘unhealthy for sensitive B. What Were the Significant Commentsgroups;’’ two new requirements, first, to Certain documents are available from and Our Responses?report a pollutant-specific sensitive the U.S. Department of Commerce, 1. Comments and Responses on Generalgroup statement when the index is National Technical Information Service, Changesabove 100, and second, to use specific 5285 Port Royal Road, Springfield, VA 2. Comments and Responses on Changes tocolors if the index is reported in a color 22161. Available documents include: the Sub-Indicesformat; new breakpoints for the ozone (1) The Review of the National C. What Are the Final Revisions?(03) sub-index in terms of 8-hour Ambient Air Quality Standards for 1. What Are the General Changes? Ozone: Assessment of Scientific and 2. What Are the Changes to the Sub-average 03 concentrations; a new sub- Technical Information (‘‘Staff Paper’’) Indices?index for fine particulate matter (PM2.5); D. What Are the Related Informationaland conforming changes to the sub- (EPA–452/R–96–007, June 1996, NTIS Materials?indices for coarse particulate matter # PB–96–203435, $67.00 paper copy and III. Regulatory and Environmental Impact(PM10), carbon monoxide (CO), and $21.50 microfiche). (Add a $3.00 Analysessulfur dioxide (SO2). In addition, EPA is handling charge per order.) A. Executive Order 12866: OMB Review ofchanging the name of the index from the (2) Review of the National Ambient ‘‘Significant Actions’’Pollutant Standards Index (PSI) to the Air Quality Standards for Particulate B. Regulatory Flexibility Analysis/SmallAir Quality Index (AQI). This document Matter: Policy Assessment of Scientific Business Regulatory Enforcement and Technical Information (‘‘Staff Fairness Actdiscusses the development of related Paper’’) (EPA–452/R–96–013, July 1996, C. Unfunded Mandates Reform Actinformational materials on pollutant- D. Paperwork Reduction Actspecific health effects and sensitive NTIS # PB–97–115406, $47.00 paper E. Executive Order 13045: Children’sgroups and on precautionary actions copy and $19.50 microfiche). (Add a Healththat can be taken by individuals to $3.00 handling charge per order.) F. Executive Order 12848: Environmentalreduce exposures of concern. This The guidance documents associated Justicedocument also discusses the with this rulemaking are available from G. Executive Order 12875: Enhancinginterrelationship between the uniform EPA’s Office of Air Quality Planning Intergovernmental Partnershipsair quality index and other programs and Standards in Research Triangle H. Executive Order 13084: Consultationthat provide air quality information and Park, NC. Requests for these and Coordination with Indian Tribal publications can be mailed to: Terence Governmentsrelated health information to the general I. National Technology Transfer andpublic, including State and local real- Fitz-Simons, EPA (MD–14), Research Triangle Park, NC 27711. Your request Advancement Acttime air quality data mapping and J. Congressional Review Actcommunity action programs. may also be phoned in to Terence Fitz- IV. References Simons at 919–541–0889, or sent by e-EFFECTIVE DATE: October 4, 1999. mail to fitz-simons.terence@epa.gov. I. BackgroundADDRESSES: A docket containing (1) Guideline for Public Reporting ofinformation relating to EPA’s revisions A. What Are the Legislative Daily Air Quality—Air Quality Indexof the air quality index (Docket No. A– Requirements? (AQI) (EPA–454/R–99–010).98–20) is available for public inspection (2) Guideline for Developing an Section 319 of the Act governs thein the Air and Radiation Docket and Ozone Forecasting Program (EPA–454/ establishment of a uniform air qualityInformation Center, U.S. Environmental R–99–009). index for reporting of air quality. ThisProtection Agency, South Conference The following document is available section directs the Administrator toCenter, Room M–1500, 401 M St., SW, from EPA’s Office of Mobile Sources ‘‘promulgate regulations establishing anWashington, DC 20460, telephone (202) (OMS) in Ann Arbor, MI. Requests for air quality monitoring system260–7548. The docket may be inspected this publication can be mailed to: throughout the United States whichbetween 8 a.m. and 5:30 p.m. on Michael Ball, US EPA—National utilizes uniform air quality monitoringweekdays, and a reasonable fee may be Vehicle and Fuel Emissions Laboratory criteria and methodology and measurescharged for copying. For the availability (NVFEL), 2000 Traverwood Dr., Ann such air quality according to a uniformof related information, see Arbor, MI 48103. Your request may also air quality index’’ and ‘‘provides forSUPPLEMENTARY INFORMATION. be phoned in to Michael Ball at 734– daily analysis and reporting of air

3. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42531quality based upon such uniform air index values serve to divide the index broadening the ways in which State andquality index * * *’’. into categories, with each category being local agencies can meet the nationally identified by a simple informative uniform AQI reporting requirements,B. What Is the History of the Air Quality descriptor. The descriptors are intended and are contributing to State and localIndex? to convey to the public information efforts to provide community health In 1976, we established a nationally about how air quality within each protection and to attain or maintainuniform AQI, called the Pollutant category relates to public health, with compliance with the NAAQS. We andStandards Index (PSI), for use by State increasing public health concerns being State and local agencies recognize thatand local agencies on a voluntary basis conveyed as the categories range to the these programs are interrelated with(41 FR 37660). This uniform index was upper end of the scale. Additional AQI reporting and with the informationestablished in light of a study conducted information about the general health on the effects of air pollution on publicby EPA and the President’s Council on effects associated with each category, health that is generated through theEnvironmental Quality (CEQ, 1976). and precautions that sensitive groups periodic review, and revision whenThis study found that the 55 urban areas and the general public can take to avoid appropriate, of the NAAQS.in the U.S. and Canada reporting an exposures of concern, has been madeindex of air quality used 14 different The most recent revisions to the O3 available through an informational and PM NAAQS, the Ozone Mappingindices, in conjunction with different booklet, updated as appropriate, thatcautionary messages, such that in Project, and community action programs also presents and explains the PSI (EPA,essence 55 different indices were being are discussed briefly below. In light of 1994).used to report air quality. This diversity the interrelationships among these In 1979, we made changes to the AQI,of indices sent a confusing message programs, we have developed today’s in part to reflect revisions to theabout air quality to the public. Based in revisions to the uniform AQI with the NAAQS for O3, and to establishpart on this study, we developed an goal of creating a revised AQI that can requirements for AQI reporting (44 FRindex to meet the needs of State and effectively serve as a nationally uniform 27598). The requirement for State andlocal agencies that has the following link across these programs. In so doing, local agencies to report the AQI appearsadvantages: it sends a clear and we intend to support and encourage in 40 CFR part 58.50, and the specificconsistent message to the public by State and local participation in real-time requirements (e.g., what to report, howproviding nationally uniform data reporting initiatives and the to report, reporting frequency,information on air quality; it is keyed as development and implementation of calculations) are in appendix G to 40appropriate to the national ambient air community action programs that serve CFR part 58.quality standards (NAAQS) and the public education and health protectionsignificant harm level (SHL) 1 which C. What Programs Are Related to the goals. AQI?have a scientific basis relating air 1. Ozone and Particulate Matter NAAQSquality and public health; it is simple Historically, State and local agencies Revisionsand easily understood by the public; it have used primarily the AQI, or otherprovides a framework for reflecting AQIs, to provide general information to On July 18, 1997, we revised thechanges to the NAAQS; and it can be the public about air quality and its primary NAAQS for O3 and PM basedforecasted to provide advance relationship to public health. In recent on a thorough review of the scientificinformation on air quality. years, many States and local agencies, as evidence linking exposures to ambient The PSI, which is also commonly well as EPA, have been developing new concentrations of these pollutants toreferred to by some State and local and innovative programs and initiatives adverse health effects at levels allowedagencies as the AQI, includes sub- to provide more information to the by the previous NAAQS. In particular,indices for O3, PM, CO, SO2, and public, in a more timely way. These we replaced the 1-hour O3 NAAQS withnitrogen oxide (NO2), which relate initiatives, including real-time data an 8-hour O3 NAAQS andambient pollutant concentrations to reporting through the Ozone Mapping supplemented the PM NAAQS with 24-index values on a scale from 0 through Project and community action programs, hour and annual standards for fine500. This represents a very broad range can serve to provide useful, up-to-date, particulate matter (measured as PM2.5 3).of air quality, from pristine air to air and timely information to the public These decisions were challenged in thepollution levels that present imminent about air pollution and its effects. Such U.S. Court of Appeals for the District ofand substantial endangerment to the information will help individuals take Columbia Circuit, and on May 14, 1999,public. The index has historically been actions to avoid or reduce exposures of the Court remanded them to the Agencynormalized across pollutants by concern and can encourage the public to for further consideration, principally indefining an index value of 100 as the take actions that will reduce air light of constitutional concernsnumerical level of the short-term (i.e., pollution on days when levels are regarding section 109 of the Act asaveraging time of 24-hours or less) projected to be in air quality categories interpreted by EPA. American Truckingprimary NAAQS for each pollutant and of concern to local communities. Thus, Associations v. EPA, Nos. 97–1440, 97–an index value of 500 as the SHL.2 Such these programs are significantly 1441 (D.C. Cir. May 14, 1999). On June 28, 1999, the U.S. Department of Justice 1 Significant harm levels are those ambient pollution, approaching the SHL, are in danger of on behalf of EPA filed a petition forconcentrations of air pollutants that present an being reached. Changes to this emergency episode rehearing seeking review of the Court’simminent and substantial endangerment to public program will be proposed in the near future.health or welfare, or to the environment, as decision by the entire Court of Appeals. Below an index value of 100, historically anestablished in 40 CFR 51.151. intermediate value of 50 was defined either as the The EPA is continuing to assess what 2 Intermediate index values of 200, 300, and 400 level of the annual standard if an annual standard further legal or administrativewere defined and are the basis for the Alert, has been established (for PM10 and SO2), or as a proceedings may be appropriate inWarning, and Emergency episode levels included in concentration equal to one-half the value of the response to the Court’s decision, as well40 CFR part 51, appendix L, as part of the short-term standard used to define an index valuePrevention of Air Pollution Emergency Episodes of 100 (for O3 and CO). Coarse or inhalableprogram. This program requires specified areas to particulate matter, PM10, refers to particles with an 3 PM 2.5 refers to particles with an aerodynamichave contingency plans in place and to implement aerodynamic diameter less than or equal to a diameter less than or equal to a nominal 2.5these plans during episodes when high levels of air nominal 10 micrometers. micrometers.

4. 42532 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulationsas its relevance to other rulemakings In this regard, the AQI is essentially a days above the numerical level of thesuch as this one. way of conveying scientific/medical standards. With respect to the present advice to the public in an easily These understandings were alsorulemaking, we have concluded that it understood form. reflected in CASAC’s advice to theis appropriate to proceed with final As indicated below, there was broad Administrator during the O3 NAAQSaction on the proposed AQI revisions. support in public comments for review, urging expansion of the publicAs indicated previously, section 319 of modifying and expanding the use of the health advisory system (i.e., a uniformthe Act requires the Agency to establish AQI to take into account the expanded AQI) and communication to the publica uniform air quality index, and this understanding of air quality-health of the apparent nonthreshold nature ofrequirement is independent of the relationships that resulted from EPA’s the health effects. More specifically, astatutory provisions governing review of the latest scientific number of CASAC panel membersestablishment and revision of the information on the effects of PM and O3. recommended ‘‘that an expanded airNAAQS. Moreover, there is no statutory Other proposed revisions were designed pollution warning system be initiated sorequirement that the AQI be linked to to enhance the effectiveness of the AQI that sensitive individuals can takethe NAAQS, although EPA has used generally. The function the AQI serves appropriate ‘exposure avoidance’NAAQS levels in the past as reference of conveying to the public information behavior’’ (Wolff, 1995). Consistent withpoints for the establishment of specific on daily air quality and associated this advice, in the preamble to thebreakpoints within sub-indices. Nothing health risks is clearly important, and the proposed revisions to the O3 NAAQSin the Court’s opinion alters the season of higher pollution levels is (61 FR 65733–65734), the Administratorconclusions EPA reached in revising the imminent. For all the above reasons, we requested comment on the usefulness ofair quality criteria for PM and O3 under see no reason to delay final action on providing specific health effectssection 108 of the Act, or in the NAAQS the proposed revisions of the AQI. The information when ambientrulemakings, concerning the occurrence remainder of this section discusses concentrations are around the numericalof specific health effects at varying aspects of the O3 and PM NAAQS level of the standard, theconcentrations of PM and O3 in the air. rulemakings as they relate to today’s appropriateness of using the AQI toRegardless of the outcome of the remand action. convey such information to the public,as to the NAAQS themselves, we believe As a result of the reviews of the the possible addition of two new AQIthe scientific record and conclusions scientific information upon which the categories (one just above and one justunderlying them are more than 1997 NAAQS for O3 and PM are based, below the numerical level of thesufficient as a basis for decisions on the an expanded understanding emerged as standard) and associated descriptorslevels at which the public should be to the nature of the relationships and levels, as well as related healthnotified about health risks associated between exposure to ambient effects and cautionary statements.with daily air quality.4 concentrations of these pollutants and Broad support for modifying the AQI We do not regard this notification the health effects likely to be was received in public comments onfunction as involving the constitutional experienced, especially near the level of this aspect of the O3 NAAQS proposal,concerns raised in the Court’s opinion. the NAAQS. We and the Clean Air as discussed in the final ruleThe AQI has no bearing on pollution Scientific Advisory Committee establishing revisions to the O3 NAAQScontrol requirements for specific (CASAC) 5 recognized that for these (62 FR 38873–38874). Commenterssources; nor does it serve to implement pollutants there may be no thresholds overwhelmingly endorsed expandingthe NAAQS involved in the litigation. below which health effects are not likely the use of the AQI for various reasons,Rather, it provides information on air to occur, but rather a continuum of although many expressed concern withquality and health that will help effects potentially extending down to the possible category descriptorsindividual citizens take prudent, self- background levels. As ambient suggested in the proposal (i.e.,protective actions to avoid or reduce concentrations increase, the proportion ‘‘moderately good’’ and ‘‘moderatelyexposures of concern and to avoid of individuals likely to experience unhealthful’’). Many commenters feltcontributing to air pollution on days effects and the seriousness of the health that an expanded AQI could helpwhen unhealthy air quality is projected. effects increase. Thus, the 1997 particularly sensitive people take action standards were not considered risk free. to minimize their exposures, and that 4 Under section 319, the levels that are While the standards were intended to the AQI could be combined withappropriate for this purpose do not necessarily protect public health with an adequate community action programs to reducedepend on the NAAQS levels that may beappropriate under section 109. Depending on how margin of safety, in accordance with ambient concentrations when thethe Agency chose to set an ambient standard, for section 109(b) of the Act, including the numerical level of the standard wasexample, it might conclude that the standard does health of sensitive groups, exposures to forecasted to be exceeded. Somenot need to preclude certain effects falling below ambient concentrations just below the commenters endorsed increasing thethe level of public health concern, and at the sametime set the AQI in such a way as to assure that numerical level of the standards may specificity of health and cautionarysensitive individuals who might experience those result in exposures of concern for the statements related to the AQI categories.effects receive notification and advice on actions most sensitive individuals. Conversely, Commenters from State and localthey might take to avoid them. Similarly, AQI exposures to ambient concentrationsvalues might be set that are higher than the agencies encouraged us to develop anystandard would permit but that would require more just above the numerical level of the approaches to revising the AQI inserious health warnings. This is not to say, standards are not likely to result in consultation with them, specifically inhowever, that the levels of the 1997 NAAQS are exposures of concern for most healthy the areas of sharing real-time monitoringirrelevant to decisions on the AQI breakpoints. To people. This expanded understanding isthe contrary, the levels of the 1997 NAAQS are data, risk communication with theuseful surrogates for a series of scientific reflected in the forms of the new public, and coordination of a nationalconclusions reached in the NAAQS rulemakings, standards, which allow for multiple program.based on the revised air quality criteria, regardingthe nature, extent, and severity of health effects 5 CASAC is a scientific advisory committee 2. Real-time Data Reporting Initiativeassociated with varying concentrations of PM and established under the Act to review the scientific (Ozone Mapping Project)O3 in the air. Accordingly, later sections of this criteria and standards and to advise thenotice make reference as appropriate to relevant Administrator on revision of the NAAQS, as The Ozone Mapping Project is part oflevels of the 1997 NAAQS. appropriate. EPA’s Environmental Monitoring for

5. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42533Public Access and Community Tracking they can protect their health and actions to the AQI being adopted today, together(EMPACT) initiative—a new approach they can take to reduce pollution. with related informational materials,to providing timely environmental will significantly improve the 3. Community Action Programsinformation to communities. It is a effectiveness of communications withcooperative effort of the EPA, State and The implementation of community these groups. Public education, orlocal air pollution control agencies, and action programs (also referred to as programs directly targeting theseregional organizations including the voluntary action programs or episodic groups, may provide the mostMid-Atlantic Regional Air Management emission control programs) is becoming significant benefits of a communityAssociation (MARAMA), the Northeast increasingly popular across the country action program. Forecasting days withStates for Coordinated Air Use as an innovative approach used to elevated pollution levels, and thenManagement (NESCAUM), the northeast reduce emissions of O3 precursors, CO, communicating effectively about airOzone Transport Commission (OTC), and PM. Motivation for implementation quality and associated health effects,the Lake Michigan Air Directors of this type of program often stems from may help these groups selectively limitConsortium (LADCO), SouthEast States local government and business concerns their outdoor activities and, therefore,Air Resource Managers (SESARM), and about the NAAQS attainment status of limit their potential for exposures ofCentral States Air Resource Agencies the area and the restrictions, additional concern.(CenSARA). During the summer of 1998, controls, and costs associated with We are committed to providing StatesEPA’s Office of Air Quality Planning being classified as a nonattainment area. and local agencies with support in theirand Standards assumed coordination of Many areas are also motivated by public efforts to meet air quality standards, tothe project. health concerns and believe that inform the public about air quality, and increasing the amount of air quality to educate the public about the impacts The Ozone Map provides simple and information available to sensitive of air pollution. The revisions to thetimely information about ground-level populations raises awareness and AQI being adopted today have as a goalO3. During the 1998 O3 season it was results in significant health benefits. the creation of a revised AQI that canavailable on EPA’s AIRNOW web site Specific goals which are usually effectively serve as a nationally uniform(http://www.epa.gov/airnow) and on associated with community action link across the range of programs (e.g.,some local television and news reports. programs include: (1) Educate the real-time data reporting initiatives,It is an animated contour map that public and enhance protection of public community action programs) that haveshows concentrations of O3, in health; (2) attain or maintain NAAQS these functions.categories ranging from good to attainment status and the associated In support of community actionmoderate to varying degrees of economic benefits; (3) meet specific programs, we have developedunhealthy, based on AQI values, as they emission reduction targets; and (4) informational materials related to thedevelop across the eastern United manage/reduce traffic congestion. AQI, including the health effects andStates. In 1998, the map was created Community action programs are cautionary statements associated withfrom real-time, hourly O3 data provided usually voluntary and generally provide each category and more detailed healthby a network of more than 400 air multiple steps that the public, business, effects information (see section II.D.),monitoring stations from South Carolina and industry can take to reduce available on the AIRNOW web site, thatto Wisconsin and Maine. When emissions when higher levels of air State and local agencies may use toaccessed on a computer, cautionary pollution are forecast to occur, enhance their community actionstatements for each category could be including in particular transportation- programs. Focusing on transportationdisplayed by running a cursor over the related measures such as trip reduction, measures that are often a majorlegend. Also available on the AIRNOW postponement of certain activities such component of community actionweb site were still maps of maximum as vehicle refueling, and maintenance of programs, EPA’s OMS has developed avalues and forecasted values, and cars. The programs emphasize educating report entitled, ‘‘Community Actionarchived animated maps. In 1999, the the public about the impact of Programs: Blueprint for Programozone mapping coverage is being individual activities on local air quality Design.’’ This document describes theexpanded to include 31 States and over and the basics of air pollution. The major steps needed to put together a1500 monitors across the eastern and educational component of these successful episodic control program andcentral U.S., and California. In addition, programs also helps to create a strong provides criteria that State and localTV weather service providers are link between environmental goals and agencies can use to examine andplanning to carry the Ozone Map and associated public health benefits. evaluate their own programs. The reportforecasts as part of their traditional Most of these programs are based on is available from OMS (see Availabilityweather packages for local TV stations. the categories of the AQI and make use of Related Information). Along with the Ozone Map, the of the AQI descriptors and relatedAIRNOW web site contains information health effects and cautionary statements II. Rationale for Final Revisionsabout O3 health effects in the ‘‘Health on action days. By linking action days In developing the revisions to the AQIFacts’’ section, and emission reduction to the AQI, local control programs hope that are being adopted today, we soughtactivities in the ‘‘What You Can Do’’ to alter individual behavior to reduce extensive input from State and localsection. It also provides links to real- emissions and to reduce exposures to agencies and from the public. Wetime data, and community action the population. In addition to reduced sponsored a workshop with State andprogram web sites, that are maintained pollutant exposure of the general local agencies, participated in numerousby State and local agencies around the population due to improved air quality, meetings, prepared and made availablecountry. The goals of the web site are to: there are other health benefits directly a staff draft revision to the AQI sub-(1) Provide real-time air pollution data associated with community action index for O3 for use during the 1998 O3in an understandable, visual format, (2) programs that can be enhanced by season, and conducted several focusprovide information about the public linkage to the AQI. Different population groups across the nation to obtainhealth and environmental effects of air groups are more sensitive to the harmful public input on the effectiveness of draftpollution, and (3) provide the public effects of the different air pollutants revisions to the AQI and related O3with information about ways in which included in the AQI, and the revisions maps and informational materials. A

6. 42534 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulationsdetailed history of the process leading to TABLE 1.—PROPOSED CATEGORY for members of sensitive groups isthe proposal and the rationale for the INDEX VALUES, DESCRIPTORS, AND entirely consistent with an original goalproposed revisions are described more COLORS that the index be based on thefully in the December 9, 1998 proposal relationships between pollutantnotice (63 FR 67818–67834). The sub- Index values Descriptor Color concentrations and adverse healthsections below contain a description of effects within various groups, e.g.,the revisions we proposed, a discussion 0–50 ............. Good ................... Green aggravation of disease in people withof the significant comments we received 51–100 ......... Moderate ............. Yellow respiratory disease and incidence of 101–150 ....... Unhealthy for sen- Orange respiratory effects in healthy people.and our responses to them, and a sitive groups.summary of the AQI we are adopting Guidance on pollutant-specific 151–200 ....... Unhealthy ............ Redtoday. 201–300 ....... Very unhealthy .... Purple cautionary statements related to the 301–500 ....... Hazardous ........... Maroon categories of the AQI is discussed belowA. What Revisions Did We Propose? in section II.D. The primary consideration that These proposed changes reflected the Consistent with the overarching goalshaped the proposed revisions was the addition of a new category above an AQI of national uniformity in the reportingimportance of providing nationally of 100, created by dividing the current of air quality, we proposed that theuniform health information associated ‘‘unhealthful’’ category into two specific colors listed in Table 1 bewith daily ambient levels of the air categories. associated with each category. While thepollutants included in the index, When air quality is in the ‘‘unhealthy AQI can be reported without the use ofconsistent with the requirement of for sensitive groups’’ range, people that colors (through text and numbers alone),section 319 of the Act for an index to are in the sensitive group, whether the when the index is reported using colors,achieve national uniformity in daily air sensitivity is due to medical conditions, we proposed to require that only thesequality reporting. More specifically, the exposure conditions, or inherent specified colors be used. Threeproposed changes to the AQI sub- sensitivity, may experience exposures of examples of AQI reports that use colorindices for O3 and PM reflected the 1997 concern. However, exposures to ambient are the color bars that appear in manyrevisions to the O3 and PM NAAQS. The concentrations in this range are not newspapers, the color scales on Stateproposed general changes to the likely to result in exposures of concern and local agency web sites, and the for most healthy people. The descriptor color contours of the Ozone Map. Westructure of the AQI were based on the ‘‘unhealthy for sensitive groups’’ was participated in many discussions withexpanded understanding that emerged chosen to convey this message clearly. State and local agencies andduring the O3 and PM reviews as to the Participants in focus groups (SAIC 1998) associations regarding which specificnature of the relationships between clearly understood that ‘‘sensitive colors should be associated with theexposure to ambient concentrations of groups’’ does not refer to the general AQI categories, particularly above anthese pollutants and the health effects public, indicating that this descriptor index value of 100. These discussionslikely to be experienced, consideration effectively communicates the intended typically were in the context of eitherof the implications of changes for the health message. This category would the Ozone Mapping Project orother pollutants, and broad input from include a caution that while perhaps of community action programs. It wasState and local agencies and the public. interest to all citizens, would be of clear that the color associated with aThe proposed general changes to the particular interest to individuals andAQI, together with related informational category can be part of the health effects families of individuals who are and cautionary message being conveyed.materials, were intended to expand the members of sensitive groups.use of the AQI to provide more Were various State and local agencies to As air quality moves into the use different colors to represent thepollutant-specific health information, ‘‘unhealthy’’ range, exposures are same category, and thus the same levelespecially when ambient concentrations associated with an increase in the of air quality, it could well send aare close to the level of the primary number of individuals who could confusing message about air quality andNAAQS. potentially experience effects and associated health effects to the public.1. What Were the Proposed General includes a greater proportion of As an alternative to requiring the useChanges? members of the general public. Based on of specified colors, we solicited input received in the development of comment on the option of a. Categories and related descriptors, the proposal, the descriptor recommending, rather than requiring,index values and colors. The AQI ‘‘unhealthy’’ appropriately characterizes the use of these colors when reportingcurrently incorporates the pollutants O3, air quality in this range. agencies choose to report the AQI inPM, CO, SO2, and NO2. Index values In addition to an increasing number of color format. In soliciting comment onrange from 0 to 500 6, and the index is exposures of concern, when air quality this alternative, we sought to allowsegmented into five categories named by moves into the ‘‘unhealthy’’ range and communities maximum flexibility indescriptor words that were chosen to above, individuals who were affected at AQI reporting, while still preserving acharacterize the relationship between lower levels, typically members of nationally uniform AQI. We, therefore,daily air quality and public health. To sensitive groups, are likely to requested that commenters addressingreflect better the current understanding experience more serious health effects this issue discuss how this more flexibleof the health effects associated with than members of the general public. To approach would satisfy the statutoryexposure to these air pollutants, we reflect this understanding, it is language requiring a nationally uniformproposed to revise the AQI categories appropriate to convey two messages in AQI if different colors may be usedand descriptors, and to associate the cautionary statements for both the across the nation to represent the samespecific colors with the categories as ‘‘unhealthy’’ and ‘‘very unhealthy’’ range of air quality.shown below in Table 1. categories. One message is directed to members of sensitive groups, and the b. Reporting requirements. We 6 For NO , the index ranges from 200 to 500, since other is directed to the general public. proposed to change 40 CFR part 58.50 2there is no short-term NAAQS for this pollutant. The use of a distinct cautionary message to require reporting of the AQI in all

7. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42535Metropolitan Statistical Areas (MSAs) 7 at-risk from different pollutants, issuing forecasted O3 concentrations. Since wewith a population over 350,000, instead advisories for all sensitive groups who have determined that forecasting wouldof all urbanized areas with a population may be affected at AQI values greater add much to the benefits of AQIover 200,000. This change was proposed than 100 clearly improves public health reporting, we indicated that we wouldfor consistency with the other protection. Therefore, the proposed rule be making available guidance onmonitoring regulations in part 58, which encouraged, but did not require, that starting a forecasting program (EPAare or will be based on MSAs. This AQI reports include: appropriate health 1999b) in an area or MSA whereproposed change would not, however, effects and cautionary statements, all forecasting is not presently done.have a significant impact on who is AQI values greater than 100, the AQI for Included in the document is guidancerequired to report, since virtually the sub-divisions of the MSA (if there are on using hourly O3 concentrations assame number of cities would be covered important differences in air quality predictors for 8-hour averages.under the proposed reporting across sub-divisions of the MSA), c. Index name. Many State and localrequirement as are covered under the possible causes for high index values, agencies encouraged us to change theexisting requirement. and the actual pollutant concentrations. name of the PSI to the Air Quality Consistent with early input from State These topics were also discussed in our Index, or AQI, since many agenciesand local agencies, we proposed to draft ‘‘Guideline for Public Reporting of already use the name AQI whenchange the rounding conventions used Daily Air Quality—Pollutant Standards reporting the AQI value to the public.to calculate index values corresponding Index (PSI)’’ that was made available on Most participants in the focus groupsto pollutant concentrations at and above the AIRLINKS web site. preferred the name AQI, commentingthe numerical level of the NAAQS to be The proposed rule emphasized the that it more clearly identified the indexconsistent with the rounding importance of forecasting the AQI by as relating to the quality of the air ratherconventions used in defining the specifying that forecasted values should than to environmental pollution inNAAQS for each pollutant. This would be reported, when possible, but did not general. Based on these considerations,avoid situations where a health advisory require that forecasted values be we solicited comment on changing thecould be issued that describes the air as reported. Given the importance of the index name from Pollutant Standardsunhealthy, when in fact the numerical O3 sub-index in a large number of Index (PSI) to Air Quality Index (AQI).level of the standard has not been MSAs, and the use of an 8-hourexceeded. 2. What Were the Proposed Changes to averaging time for calculating the O3 The proposed rule retained the the Sub-Indices? sub-index value, forecasting the O3requirements to identify the area for index value is now more beneficial than To conform to the proposed generalwhich the AQI is being reported, the before. For a health advisory system to changes to the AQI discussed above,time period covered by the report, the be effective, people need to be notified and to reflect the recent revisions to the‘‘critical’’ pollutant for which the as early as possible to be able to avoid O3 and PM NAAQS, we proposedreported AQI value was derived, the exposures of concern. Because the O3 changes to the sub-indices for O3, PM,AQI value, and the associated category sub-index is based on 8-hour O3 CO, and SO2; no conforming changes aredescriptor. Recognizing that many averages, forecasting O3 concentrations necessary for the NO2 sub-index. Theagencies use a color format to report the clearly would have increased value in proposed sub-indices are summarizedAQI, the proposed rule added the providing cautionary statements to the below in Table 2, in terms of pollutantrequirement to report the associated public. We recognized that many State concentrations that correspond tocategory color if a color format is used. and local air agencies are already breakpoints in the index, and areBecause different sensitive groups are issuing health advisories based on discussed in the following sections. TABLE 2.—PROPOSED BREAKPOINTS FOR O3, PM2.5, PM10, CO, AND SO2 SUB-INDICES O3 PM AQI value CO, 8-hr SO2, 24-hr PM2.5, 24-hr PM10, 24-hr (ppm) (ppm) 8-hr (ppm) 1-hr (ppm) (µg/m3) (µg/m3)50 ................ 0.07 ............. ................................. 15 50 4 0.03100 .............. 0.08 ............. 0.12 65 150 9 0.14150 .............. 0.10 ............. 0.16 * 100 250 12 0.22200 .............. 0.12 ............. 0.20 * 150 350 15 0.30300 .............. 0.40 (1-hr) ... 0.40 * 250 420 30 0.60400 .............. 0.50 (1-hr) ... 0.50 * 350 500 40 0.80500 .............. 0.60 (1-hr) ... 0.60 * 500 600 50 1.00 * If a different SHL for PM2.5 is promulgated, these numbers will be revised accordingly. a. Proposed ozone sub-index. On July hour average O3 concentrations protection to the public, especially18, 1997, we revised the O3 primary measured at each monitor within an children active outdoors and otherNAAQS to replace the 1-hour standard area (62 FR 38856–38896). These sensitive groups, against a wide range ofwith a new standard with an 8-hour proposed revisions were based on O3-induced health effects, includingaverage at a level of 0.08 ppm and a findings from the most recent review of decreased lung function; increasedform based on the 3-year average of the the NAAQS indicating that the new respiratory symptoms; hospitalannual fourth-highest daily maximum 8- primary standard will provide increased admissions and emergency room visits 7 A complete list of MSAs and their boundariescan be found in the Statistical Abstract of theUnited States (1998).

8. 42536 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulationsfor respiratory causes, among children average) (62 FR 38652–38760). These PM2.5 concentration to be associatedand adults with pre-existing respiratory revisions were based on findings from with a PM2.5 index value of 500 suggestdisease such as asthma; inflammation of the most recent review of the PM a continuum of effects in this range,the lung; and possible long-term damage NAAQS that recently published studies with increasing PM2.5 concentrationsto the lungs. In setting this standard, we have indicated that serious health being associated with increasingly largerrecognized that there is no apparent effects were more closely associated numbers of people likely experiencingthreshold below which health effects do with the levels of the smaller particle serious health effects (62 FR 38675; Staffnot occur, that the standard is not risk subset of PM10. These health effects Paper, p. VII–27). The proposedfree, and, thus, that exposures of include premature mortality and generally linear relationship betweenconcern are possible below the increased hospital admissions and AQI values and PM2.5 concentrations innumerical level of the standard for some emergency room visits, primarily in the this range, rounded to increments of 50extremely sensitive individuals. elderly and individuals with µg/m3 to reflect the approximate nature We proposed to set an index value of cardiopulmonary disease; increased of such a relationship, is consistent with100 equal to the level of the 8-hour O3 respiratory symptoms and disease in this evidence.standard. Recognizing the continuum of children and individuals with Proposed conforming changes to thehealth effects, we considered the results cardiopulmonary disease; decreased PM10 sub-index. Consistent with theof a quantitative risk assessment lung function, particularly in children retention of the levels of the PM10(Whitfield et al., 1996) in selecting 8- and individuals with asthma; and NAAQS, we proposed to retain the PM10hour O3 concentrations to correspond to alterations in respiratory tract defense sub-index generally and to add a newindex values of 50, 150 and 200. Since mechanisms. In addition, PM10 breakpoint at an index value of 150 tono human health effects information standards were retained at the same conform to the proposed additional AQIwas available for 8-hour average O3 levels of 50 µg/m3 (annual) and 150 µg/ category. We proposed that thisconcentrations at significantly higher m3 (24-hour average) to continue to breakpoint be set at a PM10 24-hourlevels, we proposed to retain the provide protection against health effects average concentration of 250 µg/m3, thebreakpoints at the upper end of the AQI associated with the coarse particle mid-point between the breakpointsscale (between the ‘‘very unhealthy’’ subset of PM10, including aggravation of associated with index values of 100 andand ‘‘hazardous’’ categories and the SHL asthma and respiratory infections. To 200. We believe that the PM10 sub-which corresponds to the top of the PSI reflect these revisions to the PM index, with this conforming change,scale of 500) in terms of the existing 1- NAAQS, we proposed to add a new sub- remains appropriate for the publichour average concentrations. index for PM2.5, and to make conforming health protection purposes of the AQI. These proposed revisions reflect the changes to the sub-index for PM10, c. Proposed conforming changes tonew 8-hour O3 NAAQS and will in consistent with the proposed general the CO and SO2 sub-indices. Since thealmost all areas result in a more changes to the AQI. The proposed sub- current AQI sub-indices reflect theprecautionary index than the current 1- indices are summarized in Table 2 and current NAAQS for CO and SO2, thehour sub-index. However, we discussed below. only change we proposed for these sub-recognized that a very small number of Proposed new PM2.5 sub-index. indices was to add a breakpoint to eachareas in the U.S. have atypical air Consistent with the historical method of sub-index at an index value of 150 toquality patterns, with very high 1-hour selecting breakpoints of the AQI, we conform to the proposed additional AQIdaily peak O3 concentrations relative to proposed to set an index value of 100 category. We proposed that thesethe associated 8-hour average at the level of the 24-hour PM2.5 breakpoints be set at concentrations atconcentrations. In such areas, the use of NAAQS, 65 µg/m3, and an index value the mid-points between the breakpointsthe current 1-hour sub-index may be of 50 at the level of the annual NAAQS, associated with index values of 100 andmore precautionary on a given day than 15 µg/m3. Also consistent with the basic 200, consistent with the approachthe proposed 8-hour sub-index. To structure of the AQI, the proposed described above for conforming changesallow for the reporting of the more upper bound index value of 500 to both the 1-hour O3 sub-index and theprecautionary sub-index value, we corresponds to the SHL, established in PM10 sub-index. These proposedproposed to retain the 1-hour sub-index section 51.16 of the CFR under the breakpoints are summarized in Table 2at and above AQI values of 100 and to Prevention of Air Pollution Emergency and will be reviewed in conjunctionallow the reporting of the higher of the Episodes program. The SHL is set at a with the future reviews of the CO andtwo O3 sub-index values. Thus, both the level that represents an imminent and SO2 NAAQS.new 8-hour and the current 1-hour sub- substantial endangerment to publicindices, as shown in Table 2, were health. When we propose revisions to B. What Were the Significant Commentsincluded in the proposed appendix G. the Prevention of Air Pollution and Our Responses?Since for the large majority of areas the Emergency Episodes program, the This section describes the significant8-hour sub-index will be more proposal will include a SHL for PM2.5. comments we received on proposedprecautionary, we did not propose to In the interim, we proposed to establish revisions to the index and our generalrequire all areas to calculate both sub- a PM2.5 concentration of 500 µg/m3 to be responses to them. More detailedindex values. Rather, we proposed to associated with a PM2.5 index value of comment summaries and responses areallow areas the flexibility to calculate 500. contained in a Response to Commentsboth sub-index values and, when both For intermediate breakpoints in the Document that is available in the docketsub-index values are calculated, to AQI between values of 100 and 500, (see ADDRESSES).require that the higher value be PM2.5 concentrations were proposedreported. We specifically solicited that generally reflect a linear 1. Comments and Responses on Generalcomment on this proposed approach. relationship between increasing index Changes b. Proposed PM sub-index. On July values and increasing PM2.5 values. The a. Categories and related descriptors,18, 1997, we revised the PM NAAQS by available scientific evidence of health index values and colors. With regard toadding a new set of standards for fine effects related to population exposures the proposed changes to the generalparticles, or PM2.5, set at levels of 15 µg/ to PM2.5 concentrations between the 24- structure of the index, we receivedm3 (annual) and 65 µg/m3 (24-hour hour NAAQS level and the proposed comments that focused on two major

9. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42537issues. The first major issue was air pollution warning system (to) be initiated public. As noted by one Statewhether to add a category above or so that sensitive individuals can take commenter:below the standard, or both. In addition, appropriate exposure avoidance behavior,’’ however EPA has misrepresented the health We are satisfied and support the proposedrelated to that issue were comments category index values, descriptors and colors. threat with the levels it has proposed.about the proposed descriptor for the (Docket No. A–98–20, IV–D–17). [We] believe that the Air Quality Index * * *category we proposed to add above the has been a very effective communication toollevel of the standard. The second major A State commenter that supported during the ozone season. It has been ourissue regarded the particular colors, adding a category below the level of the experience that a category above the standardlisted in Table 1, we proposed to standard observed that adding such a provides the proper communication to the affected populations without alarming orassociate with each category. category would be consistent with desensitizing others. (Docket No. A–98–20, With regard to the general structure of EPA’s conclusion ‘‘that exposures to IV–G–04).the index, most commenters supported ambient concentrations just below theour proposal to add a category above the numerical level of the standard may Further, given the changes we havelevel of the standard. However, result in exposures of concern for the made to the PM2.5 sub-index, and thecommenters from environmental groups most sensitive individuals.’’ (Docket No. expanded ‘‘moderate’’ range and theand several States suggested adding a A–98–20, IV–D–19). cautionary statements we have madecategory below the level of the standard available in guidance for use below the We understand and agree with theto provide additional caution for level of the 8-hour O3 standard, we do issues related to communication of riskmembers of sensitive groups, instead of, not believe a category below the level of below the levels of the 24-hour PM2.5 the standard to caution members ofor in addition to one above. These and 8-hour O3 standards. For the PM2.5commenters expressed the view that the sensitive groups would be an sub-index, we have addressed concerns appropriate distinction for any of theproposed sub-indices, that added a about health effects below the level ofcategory above the standard, did not pollutants included in the index. We the 24-hour PM2.5 standard by revising believe that the approach we havesufficiently caution members of the PM2.5 sub-index so sensitive groupssensitive groups about health effects adopted retains the simplicity of the are cautioned below the 24-hour PM2.5 index while allowing for more detailedoccurring below the level of the standard. Based on review of thestandard. Specifically, their comments cautionary information to be made suggested revisions to the PM2.5 sub- available to the public whenwere in reference only to potential index that we received in comments, wehealth effects occurring below the 8- appropriate. believe this approach fully addresses With regard to the descriptorhour O3 and 24-hour PM2.5 standards. their concerns. The revision isRegarding health effects below the PM2.5 ‘‘unhealthy for sensitive groups,’’ some discussed in section II.B.2 below. commenters expressed the view thatstandard, one State commenter took For better communication of health this descriptor is misleading because itexception with the statement in the risk below the 8-hour O3 standard, we encompasses a large segment of theproposal that an additional category have addressed the issues raised by population. In addition, they argued, thebelow the standard, while perhaps commenters by revising the O3 sub- public will not know that for certainmeaningful for O3, would not be an index. We have expanded the pollutants healthy people, especiallyappropriate distinction for the other ‘‘moderate’’ range of the 8-hour O3 sub- healthy children, are members ofpollutants in the index. This commenter index to make it more precautionary. sensitive groups. Noting that it isnoted that ‘‘such a distinction would be When air quality is in the ‘‘moderate’’ prudent policy to assume that most riskmore imperative for other pollutants, range of the 8-hour O3 sub-index, we communication regarding air qualityespecially for PM where the level of the have provided health effects and impacts will be limited to the general24-hour standard may be less protective cautionary statements, available in our descriptors, some of these commentersof sensitive groups than the ozone AQI Reporting Guidance document requested that if we continue tostandard.’’ (Docket No. A–98–20, IV–D– (EPA, 1999a) (discussed in section II.D), distinguish sensitive groups from the19). Agreeing with the importance of that may be used by State and local general population, that the descriptorcautioning sensitive groups below the agencies to caution unusually sensitive be changed from ‘‘unhealthy forlevel of the 24-hour PM2.5 standard, individuals below the level of the 8- sensitive groups’’ to ‘‘unhealthy foranother commenter noted ‘‘We believe hour O3 standard. This revision is children and other sensitive groups,’’ sothat adding a category below the level discussed in section II.B.2 below. that the public would receive a clearof the standard is of particularimportance with respect to fine We do not believe it is necessary or message that children are members of aparticles.’’ (Docket No. A–98–20, IV–D– appropriate to change the general sensitive group that may be at increased11). Regarding the O3 sub-index, some structure of the index by adding a new risk from exposure to ozone. (Docketof the States and the environmental category below the level of the standard No. A–98–20, IV–D–2, IV–D–4 and IV–groups that endorsed adding a category to caution extremely sensitive D–11). We agree with the view of thesebelow the level of the standard individuals. Based on the concerns of commenters, based on the responses ofsupported that position by noting that State and local agencies that the participants in the focus groups, that thewe and CASAC stated that extremely addition of two new categories would public will not know that healthysensitive individuals may be affected unduly complicate the index, we are people, including healthy children, maydown to background levels of O3. One adding just one new category to be at risk when air quality is in thecomment from an environmental group maintain the degree of simplicity ‘‘unhealthy for sensitive groups’’ range.noted that: strongly supported by State and local The suggested descriptor, however, is agencies, none of whom advocated the only appropriate for pollutants forThe CASAC recognized that for O3 and fine addition of two new categories. As which children are a sensitive group.particle pollution, ‘‘there are no discernible described in section II.A.1 above, we Since the sensitive groups differ fromthresholds below which health effects are notlikely to occur in the most sensitive believe that adding a category above the one pollutant to another, and childrenindividuals’ as it was advising EPA to set level of the standard makes a distinction are only part of the sensitive group fornew health standards. We agree with CASAC that is useful for members of sensitive O3, PM2.5 and NO2, this descriptor is notand support the idea of setting ‘‘an expanded groups without alarming the general appropriate for the other pollutants. For

10. 42538 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulationsexample, the descriptor ‘‘unhealthy for the same or a similar color scheme below the level of the standard, aschildren and other sensitive groups’’ noted that it effectively and described above.would not be appropriate for use in the appropriately portrayed the full range of In considering these comments, weCO sub-index, where people with heart local air quality values. On the other recognize that the NAAQS are set todisease are the group most at-risk. Use hand, some environmental groups and protect public health with an adequateof this descriptor when CO levels are several States commented that the color margin of safety, including the health ofabove an index value of 100 could lead red should be used for the category just sensitive groups. When the standardsto confusion about the health effects above standard, instead of the color are met, public health is protected.associated with high levels of CO. orange that we proposed. Primarily, Exposures to ambient concentrationsTherefore, we do not believe it would be these commenters expressed the view just above the numerical level of theuseful or prudent to adopt the that the color orange would not send a standards are not likely to result indescriptor ‘‘unhealthy for children and sufficiently strong message that the exposures of concern for most healthyother sensitive groups.’’ To increase standard has been exceeded. In the people. This is especially true for the 8-public awareness that healthy children proposal we indicated that because the hour O3 standard, which has aare members of the sensitive group for color red sends a strong cautionary concentration-based form designed toO3, we are adding the requirement that message, it is most appropriately used offer more protection from higherwhen the AQI value is above 100, when effects are likely to occur in the concentrations than from multiplereporting agencies include in their general population, and when more smaller exceedances of the standard.published report a statement describing serious effects are likely in members of The form of the 8-hour O3 standardthe sensitive group for that particular sensitive groups. Many of these allows for multiple days above the levelpollutant. The reporting requirement for commenters noted that since up to 30 of the standard, provided the 3-yearpollutant-specific statements describing percent of the population could be average of the fourth-highest maximumsensitive groups is discussed below in considered to be in the sensitive group concentrations does not exceed the levelsection II.C.1.b on reporting for O3, when the standard is exceeded of the standard. This means that publicrequirements, and listed in appendix G. the general public should be alerted. health is protected, even when there areWe believe that the requirement for These commenters expressed the view multiple days each year when ambientagencies to report the pollutant-specific that it is appropriate to use the color red O3 concentrations are above the level ofstatements identifying the groups at just above the level of the standard both the standard, as long as the standard isrisk, when air quality is above an index to alert the public of potential health met. Therefore, it is inappropriate onvalue of 100, will more effectively risks and to encourage emission any given day to express a high level ofcommunicate the risk associated with reduction actions. An environmental concern when air quality just exceedsspecific air pollutants, and thereby group commented: the level of the standard. Besidesbetter help members of the public While individuals that are sensitive to poor sending an inaccurate health effectsreduce personal exposure. To the extent air quality may look at the daily listing in the message by using the color red with thepossible with AQI reporting, this newspaper or call a message recorded by the category ‘‘unhealthy for sensitiverequirement will also ensure that the state or local air agency, we know from groups,’’ another concern is thepublic is informed that children are part experience that air quality does not receive potential loss of credibility that couldof the sensitive group for O3. This broad public attention until it is predicted or result from repeatedly sending a signalrequirement will not only improve reaches the level of ‘‘code red.’’ At that point, disproportionate to the expectedprotection for healthy children, but also the television and radio media announces incidence of noticeable symptoms. If that people should restrict outdoor activityhealthy adults, the elderly, and people this were to happen, the AQI could lose and take steps to not add more pollution towith heart and lung disease. We believe the air by carpooling, using less electricity, the power to influence people’sthat another good way to address this or using mass transit. (Docket No. A–98–20, behavior to protect their health. Onelack of awareness is to educate the IV-D–17). commenter from a State agencypublic, and the media and health care expressed this concern: Another commenter from a Stateprofessionals that inform the public, One of our key concerns * * * is that the agency noted:about the health effects message general public will become ambivalent if weassociated with the category ‘‘unhealthy Considering that the definition of sensitive forecasted 20, 30, or more Code Red daysfor sensitive groups.’’ To help individuals for ozone includes healthy active over the course of an ozone season. Under children and outdoor workers, a clear this scenario, people may not take adequateaccomplish the goal of educating the unambiguous message needs to be sent to the precautions to protect themselves when anpublic, we will be expanding the public so that they can respond accordingly. actual unhealthy level is reached. (Docketdevelopment of education and outreach For parents of active children, a message No. A–98–20, IV–G–05).materials and activities as described in which states that air quality is unhealthy,section II.D below. and displays it using the color red, sends a A commenter from another State clear message—even though it may carry agency expressed a similar view: With regard to the colors listed inTable 1, we received comments with it the risk that individuals not in the It is important to make sure that this sensitive population might also take general message is not jeopardized byconcerning both the particular colors exposure avoidance measures. Issuing a treating the new 85 ppb, 8-hour standard asassociated with the different categories message that air quality is unhealthy for the bright line between healthy andand whether specific colors should be sensitive individuals and displays it with a unhealthy. The Code Red message will not berequired or recommended. The majority code orange runs the risk of having sensitive considered credible if it is issued between 40of commenters, including most State individuals, or those guiding sensitive to 60 times a summer in our area. Last yearand local agencies commenting, individuals (i.e., doctors and parents) not there were 54 days * * * where the 8-hoursupported our proposed color scheme. prescribe any avoidance action because of the standard was exceeded. (Docket No. A–98–Many of those (commenters that did ambiguity of the message. (Docket No. A–98– 20, IV–G–13).support it), had used the same or a 20, IV-G–19). From the comments we have receivedsimilar color scheme associated with Additionally, these commenters and from our focus group research, weeither community action programs or suggested that the color orange be used believe that the color red sends tooozone maps. Commenters that had used for the category they wanted us to add strong a message for use in the

11. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42539‘‘unhealthy for sensitive groups some pollutants includes healthy air pollution problems is to becategory.’’ Additionally, based on the children and adults, be alerted to communicated effectively.’’ (Docket No.comments of State and local agencies potential health risks and that the A–98–20, IV–D–01).that have used the same or a similar general public be motivated to take In response to the first commenter’scolor scheme, we believe that the color emissions reductions measures when air objections, we do not believe thatorange sends an appropriate health quality is above the level of the requiring specific colors presents anymessage and yet a strong message that standard. In response to the concerns particular enforceability problems. Thisthe standard has been exceeded. One expressed by these commenters, we are requirement is one of many contained inState commenter noted that their planning to significantly step up the the 40 CFR part 58 Ambient Air Qualityenvironmental agency: development of education and outreach Surveillance requirements and would be materials and increase activities to get enforceable in the same manner and tohas been using a green/yellow/orange/redcommunication system since 1993. The this message out, as discussed in section the same extent as any othermedia has used the red, orange and yellow II.D below. requirement of this section. As such, weair quality codes to convey a ‘‘the air is not Only two commenters recommended believe there is no difference inclean’’ message. In general, the media has against requiring specific colors. The enforceability between this and aused Code Red to convey a message that air first commenter did so on the grounds requirement for the use of particularpollution is or will be at a near emergency that requiring specific colors would be descriptors or air quality index values.level. Code Orange has connoted ‘‘very unenforceable, and may lead to We expect to work with EPA Regionaldirty.’’ Code Yellow has, in general, been frustration and conflict. While Offices to ensure that they monitor Stateused to characterize air pollution as not too applauding our goal of establishing a implementation of the revised AQI andbad—but still not clean. (Docket No. A–98– consistent message, and agreeing that it work with the States to encourage20, IV–G–13). is good to have as much national compliance. Another State commenter noted: consistency as possible, this commenter With regard to comments that our We disagree, however, with * * * [the] noted that efforts to legislate aesthetics requirement would preclude States fromassertion that the ‘‘Code Orange’’ message in are uncomfortable, unwieldy and using other color schemes and actionthe PSI does not adequately protect public ultimately unnecessary. (Docket No. A– levels in their voluntary programs, it ishealth. Our experience * * * has been that 98–20, IV–D–11). The second important to note that the AQI addressesthe health message can be effectively commenter noted that some States may the reporting of measured air qualitydelivered for Code Orange levels. We have elect to use Code Red for ozone action and does not impose any requirementsreceived much feedback from the general or limitations on community actionpublic about our ozone action day program, programs at levels other than what is being proposed and the regulation programs based on air quality forecasts.and the resounding message has been: Thank should not preclude them from doing We recognize that a nationally uniformyou for this program, I can now plan my dayto avoid exposure to high levels of ozone. that. (Docket No. A–98–20, IV–D–19). color scheme for AQI reporting will, as(Docket No. A–98–20, IV–G–05). On the other hand, there was very a practical matter, complicate a State’s strong support in the comments for us efforts to use other color schemes in In addition, ozone mapping projects action programs based on predicted airhave successfully represented air to require that agencies that use color, use specific colors in AQI reporting. All quality, but they remain free to do soquality using the full AQI color scheme. under our regulations.In the Ozone Mapping Project, of the other commenters that addressed this issue, including a commenter from Because it is the fundamental goal ofdescribed in section I.C.2, the proposed the AQI to provide nationally uniformAQI color scheme was used successfully an environmental organization, supported requiring specific colors for information about daily air quality andduring the 1998 O3 season. Participating the public health messages that areState and local agencies and regional all State/local agencies using a color format. The commenter from an appropriately associated with variousorganizations have selected the same daily air quality levels, in a format thatcolor scheme for use in the 1999 O3 environmental group noted: is timely and easily understood, weseason. Having used the proposed color EPA states that revisions to the PSI have continue to believe that requiringscheme in their local O3 map, one as a goal the creation of a nationally uniform specified colors when the AQImetropolitan air agency noted that link across a range of programs. We urge that this uniformity be achieved through the use categories are reported in color format is‘‘EPA’s proposed color scheme of a national public health warning system both necessary and appropriate. Neithercommunicates clearly in a logical that is clear to the public. To this end, we of the commenters opposing thisprogression which in our experience is do support the EPA requiring that when requirement addressed how a morealready understood by the public and colors are used by a state in its PSI, that the flexible approach of recommendingthe media.’’ (Docket No. A–98–20, IV– same color system incorporated in the PSI, specific colors, thereby allowing the useG–11). and not variants, be utilized by such state. of different colors to represent the same Because we believe the proposed (Docket No. A–98–20, IV–D–21). range of air quality, would satisfy thecolor scheme effectively and One of the many State commenters statutory language requiring a nationallyappropriately communicates the health agreeing with us that such a uniform air quality index. Therefore, weeffects message that was the basis for requirement was necessary for national are adopting the requirement, assetting the O3 and PM standards, we uniformity, noted that ‘‘Specific colors specified in appendix G below, thathave adopted the color scheme as * * * associated with each category when State and local agencies report theproposed. However, we strongly agree should be required for national AQI in a color format, that the specificwith the views expressed by uniformity and ease of understanding. colors listed in Table 1 be associatedcommenters that it is important for the Anything less would defeat the purpose with each category.health effects message associated with of a national index for comparing air b. Reporting requirements. Wethe category ‘‘unhealthy for sensitive quality in different locales.’’ (Docket No. received significant comments ongroups’’ to be effectively communicated A–98–20, IV–D–07). Another State several issues related to the reportingto the public, health care providers and commenter made the point that requirements, including the populationthe media. It is very important that ‘‘Consistency of message is important, threshold and other aspects of themembers of sensitive groups, which for especially if the regional nature of many reporting requirements, the appropriate

12. 42540 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulationsmethod of monitoring and reporting the through the State Implementation Plans comment, section 8 of appendix GPM sub-indices, the effect of AQI (SIPs). Guidance for air quality planning describes exceptions under which AQIchanges relative to the SHL program, and implementation in MSAs that fall reporting becomes discretionary, eitherand the effective date of the final rule. within the boundaries of more than one for one pollutant or the entire index, forSince we received no significant State generally calls for the participating areas with good air quality. Regardingcomments on our proposal to change the State and local agencies to identify, in these exceptions, a State commenterrounding conventions for calculating the SIPs for those States, who will be suggested that we require a minimum ofthe index to make them consistent with responsible for the preparation and 2 years at an AQI value lower than 50the rounding conventions used in submission of the required elements, before allowing agencies to ‘‘opt out’’ ofdefining the NAAQS, we are adopting including AQI reports. Where a local or reporting the AQI for a particularthat revision as proposed. With regard regional planning organization has been pollutant, so that for example, oneto the population threshold, one designated to carry out such unusually good O3 season would notcommenter expressed the view that the requirements, such an organization is make it possible for an agency to avoidchange from requiring AQI reporting in the appropriate one to report the AQI. reporting high index values inurbanized areas with a population In any case, we encourage AQI reporting subsequent O3 seasons. (Docket No. A–greater than 200,000, to requiring on the sub-MSA level, especially where 98–20, IV–D–06). We believe thatreporting in MSAs with populations the AQI differs within the MSA. requiring 2 years of index values lowergreater than 350,000, would raise the Another commenter urged us to than 50 before allowing State and localthreshold for the requirement and expand the requirement for AQI agencies discretion in reporting, whileappear to mean that large segments of reporting to areas with populations less appropriate in some situations, may bethe U.S. population would not have than 350,000, if these areas are likely unnecessary in others. We agree withaccess to AQI reporting. (Docket No. A– not to be in attainment for the 8-hour O3 this commenter that it is appropriate to98–20, IV–D–03). We have adopted the standard. To support this position, the require reporting of higher index values,requirement for AQI reporting in MSAs commenter noted that O3 can be even if air quality has been goodwith populations greater than 350,000 to transported long distances downwind throughout the previous year. Therefore,be consistent with the State/Local Air from where it is generated, resulting in we have revised section 8 of appendixMonitoring Stations (SLAMs) serious air quality problems in G, such that when the criteria for anmonitoring regulations in 40 CFR part downwind rural and smaller urban exemption are no longer met, the58, since AQI reporting is based on areas. (Docket No. A–98–20, IV–G–27). responsible agency is required to reportinformation from SLAMS monitors that We agree with this commenter that the AQI. Another commenter expressedare located and reported within the downwind areas may be significantly the view that we should strengthen thecontext of MSAs. The use of MSAs also affected by transport of O3 and minimum notification requirements, soprovides for more stable reporting areas precursors. In section 5 of appendix G, that when the AQI value exceeds 100,since MSAs are usually defined by we encourage States to evaluate air State and local agencies are required tocounty boundaries that typically do not quality in affected areas downwind of report the index to all three mediachange, whereas the boundaries for MSAs to identify the potential for (print, radio and television) to helpurbanized areas are very irregular, may significant transport-related air quality ensure that the public is informed thatinclude parts of counties, and may impacts and to expand their AQI the standard has been exceeded. (A–98–change with each census. In selecting reporting to address these situations. We 20, IV–E–3) We agree that it is important have also changed the language in thisthe MSA population threshold of to inform the public when the AQI is section such that the affected area need350,000, we tried to make the new above 100, and therefore have not be contiguous to the reporting MSA.reporting requirement equivalent to the On a related topic, one commenter strengthened the reporting provisions inold one. Under the new requirement, noted an example in which a MSA with section 6 of appendix G. In particular,virtually the same number of cities will a population greater than 350,000, has when the AQI exceeds 100, reportingbe required to report the AQI as were not registered AQI values in excess of 50 agencies should expand reporting to allpreviously. Because urbanized areas and (such that AQI reporting would be major news media, and at a minimum,MSAs are not equivalent, we realize that discretionary), although values above should include notification to the mediasome areas will be required to report the 100 are registered infrequently at a with the largest market coverages for theAQI that were not required to do so national monument within the larger air area in question.before this rulemaking, and vice versa. basin. (Docket No. A–98–20, IV–G–17). Looking at these reporting provisionsThe regulation does not preclude any This commenter requested that we more broadly, we believe that it wouldarea from reporting the AQI, and we revise the reporting requirements to add be very beneficial for reporting agenciesencourage State and local air agencies to an air quality consideration to the to educate the media about alternativereport the AQI whenever possible so population threshold as a second sources for this information, such asthat people will be informed about local component of AQI reporting. To address web sites and community actionair quality. one part of this comment, we encourage programs. Many State and local agencies Another commenter noted that some State and local air agencies to report the have web sites that provide quick accessMSAs fall within the boundaries of AQI and issue forecasts for national to timely and accurate air quality andmore than one State, and requested that parks or monuments whenever possible, related information. For State and localwe identify which of the two or more since these are places people go to for agencies participating in the Ozonereporting agencies would be responsible activities that often involve prolonged Mapping Project, the media could befor reporting the AQI for the MSA. or vigorous exertion, thereby increasing directed to the AIRNOW web site as a(Docket No. A–98–20, IV–G–15). We the risk from air pollution. We have source of information about O3 airexpect that decisions about AQI worked with the National Park Service quality and associated health effects forreporting in multi-State MSAs will be to develop appropriate guidance for yesterday, today and tomorrow. Inmade by participating agencies in the visitors and staff to use when index addition, this web site provides in-same manner as decisions about values are expected to be above 100 for depth information about O3 healthactivities to implement the standards O3. To address the other part of this effects, sources of emissions and simple

13. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42541measures people can take to improve air bound of the ‘‘unhealthy’’ category, changing the name of the index to thequality. Community action programs rather than the lower bound of the ‘‘very Air Quality Index, or AQI.also provide timely and accurate unhealthy’’ category, as it has been 2. Comments and Responses on Changesinformation, and are often used to historically. Since the AQI breakpoint of to the Sub-Indices.inform the public when air quality is 200 is also commonly used as the ‘‘Alertpredicted to be above an index value of Level,’’ or the first stage of an air All of the comments we received on100. Tools and programs such as these pollution emergency episode in proposed changes to the sub-indicescan significantly improve the timeliness example guidance associated with the focused on the sub-indices that wereof AQI reporting and provide additional SHL program, this commenter requested added for O3 (8-hour) and PM2.5. Sinceuseful information. We believe that, in that we leave the AQI value of 200 as we did not receive specific commentsthe near future, the AQI will be reported the lower breakpoint of the ‘‘very on the conforming changes we proposedby the regional and national media in unhealthy’’ category, so that emergency to the CO, SO2 and PM10 sub-indices,ways, such as the Ozone Map, that will episodes would start when air quality is we are adopting these sub-indices asnot be limited to specific MSAs. This classified as ‘‘very unhealthy’’ and proposed.type of approach will help provide AQI include appropriate-sounding health a. Ozone sub-index. We receivedreporting for areas that would otherwise effects and cautionary statements. significant comments on two issuesnot be covered, including, in some (Docket No. A–98–20, IV–D–22). We are related to the O3 sub-index. The firstcases, rural and small urban areas and adopting the breakpoints as proposed, group of comments was in response tonational parks. because we believe that it is important our request for comment on retaining Regarding reporting the PM sub- to be consistent in the treatment of the the 1-hour O3 sub-index in addition toindices, one commenter requested that category boundaries (e.g., 51 to 100, 101 the 8-hour O3 sub-index. The secondwe clarify whether PM2.5 and PM10 to 150, 151 to 200, etc.). When we group of comments focused on theshould be treated as one pollutant (e.g., appropriateness of providing propose revisions to the requirements ofreported simply as PM) or two different precautionary language below the level the SHL program, we plan to change allpollutants (e.g., reported separately). of the 8-hour O3 standard. Regarding the references to the ‘‘Alert Level’’ so they(Docket No. A–98–20, IV–D–19). We 1-hour sub-index, almost all of the will refer to air quality that exceeds theexpect State and local air agencies to comments that addressed this issue ‘‘Alert Level,’’ rather than to air qualityreport PM2.5 and PM10 separately, since supported retaining the 1-hour O3 sub- that reaches the ‘‘Alert Level.’’ However,there are two separate sub-indices with index. However, one State commenter State and local agencies should notdifferent sensitive groups, and different expressed the view that the proposal change their emergency episode plans athealth effects and cautionary was unclear regarding how areas that this point simply because we arestatements. In response to this have not attained the 1-hour O3 adopting this consistent approach to standard are to use the new 8-hour O3comment, we have added clarifying setting AQI breakpoints. Eventually,language to section 9 in appendix G. In sub-index. This commenter also noted some agencies may have to revise that it might be confusing to report theaddition, many commenters noted that emergency episode plans because weat the present time there is very little AQI based on the 8-hour O3 sub-index have revised the AQI value of 200 for in an area where the 1-hour O3 standardmonitoring for PM (both PM2.5 and the 8-hour O3 sub-index. But we do notPM10) that is suitable for use in daily had not yet been attained. (Docket No. expect States to make any revisions to A–98–20, IV–D–07). We are requiringAQI reports, and requested guidance for their emergency episode plans until we that all State and local agencies thatthe use of non-reference methods for the promulgate the revised requirements. report the AQI for O3 calculate the 8-purpose of AQI reporting. Since PM is Finally, several commenters noted that hour O3 sub-index, even if the reportingoften measured at intervals longer than in the proposal, we did not specify an area has not attained the 1-hourevery 24-hours, State and local agencies effective date for the final revisions. standard. In addition to calculating theare encouraged to use monitoring data Some of these commenters suggested 8-hour O3 sub-index, which is required,from continuous PM monitors for use in that we extend the effective date, with the reporting agency may also calculateAQI reporting, whenever possible. As suggestions ranging from 60 days to the 1-hour O3 sub-index, but this is notnoted by commenters, due to the lack of more than a year after publication. We required. However, if the reportingappropriate monitoring information, at are adopting an effective date of 60 days agency calculates both O3 sub-indexthis time it may not be possible to reportthe AQI for PM in many locations. To after publication. We believe that this values, it is required to report the higherassist State and local agencies in the use will allow adequate time for State and index value of the two. The AQI doesof non-reference methods, we have local agencies to revise daily AQI not relate to attainment status; rather, itadded language to section 10 of reports. We recognize that it may take is a tool for reporting daily air qualityappendix G stating that non-reference longer to revise related informational and associated health information. Wemethods may be used for the purpose of materials, such as printed documents, or are retaining the 1-hour O3 sub-indexAQI reporting if it is possible to related programs that agencies may only because we recognize that there aredemonstrate a simple linear relationship want to revise. However, since this a very small number of areas in the U.S.between the non-reference and the rulemaking applies only to the that have atypical air quality patterns,reference methods. requirements for daily reporting of air with very high 1-hour daily peak O3 Regarding the effect of changes to the quality, we believe an effective date of concentrations relative to 8-hourAQI on the SHL program, we received 60 days is adequate. average concentrations. In such areas,two significant comments. One c. Index name. All commenters that an index value greater than 100 mightcommenter noted that our proposed expressed a view on the index name be calculated using the 1-hour sub-changes to the categories, to standardize supported changing the name of the index, even when the 8-hour sub-indexthem such that the upper bound falls on index from the Pollutant Standards might be below 100. For these areas, thean even number, rounded to 50 (e.g., Index (PSI) to the Air Quality Index use of the 1-hour sub-index is clearly200), and lower bound falls on an odd (AQI), because this name clearly more precautionary. Because our majornumber (e.g., 201), resulted in the AQI identifies the index as relating to the interest is that appropriatebreakpoint of 200 being the upper quality of the air. Accordingly, we are precautionary messages be issued, we

14. 42542 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulationsare not retaining a complete 1-hour O3 notice’’ associated with moderate air for a pollutant (in this case, the 24-hoursub-index with ‘‘good’’ and ‘‘moderate’’ quality is inconsistent with the 8-hour PM2.5 standard) and the AQI value of 50categories. Likewise, when ambient 8- O3 standard because the standard is at the level of the annual standard, ifhour O3 concentrations are greater than intended to protect public health, even there is one, or at one-half the level of0.374 ppm, reporting agencies must the health of sensitive populations, with the short-term standard.8 This methodcalculate the index value using the 1- an adequate margin of safety, the of structuring the index is appropriatehour O3 sub-index. This is because no industry commenter expressed the view for a ‘‘typical’’ suite of air-qualityhuman health effects information is that we should omit from our materials standards, which includes a short-termavailable for higher 8-hour average O3 the health effects and cautionary standard designed to protect against theconcentrations to use as a basis for statements suggesting that air quality health effects associated with short-termselecting 8-hour breakpoints and for meeting the level of the standard is a exposures and an annual standarddeveloping appropriate health effects threat to health. We agree with the designed to protect against health effectsand cautionary statements. We believe industry and State commenters that associated with long-term exposures. Inthat since State and local agencies are since the 8-hour O3 standard is intended such cases, the short-term standard inrequired to report the name of the to protect public health, including the effect defines the level of healthpollutant responsible for an index value health of sensitive groups, with an protection provided against short-termgreater than 100, but not the associated adequate margin of safety, that the term risks and thus is a useful benchmarkaveraging period, using the 8-hour O3 ‘‘limited health notice’’ may be against which to compare daily air-sub-index should not be confusing in misleading. However, we continue to quality concentrations.areas that have not yet attained the 1- believe that it is appropriate to provide In the case of the PM2.5 standards,hour O3 standard. guidance with cautionary language for however, EPA took a different approach extremely sensitive individuals, not to protecting against health risks Regarding the issue of alerting populations or groups, below the level associated with short-term exposures.sensitive individuals below the level of of the standard. This approach is For reasons discussed in the preamblethe 8-hour O3 standard, some consistent with the advice of CASAC, to the final standards, the annual andcommenters not only suggested adding and the way we discussed expanding 24-hour PM2.5 standards were designeda category below the level of the the use of the AQI, specifically to to work together for this purpose, andstandard, but also suggested reducing caution extremely sensitive individuals the intended level of protection againstthe lower bound of the ‘‘moderate’’ below the level of the O3 standard, in short-term risk is not defined by the 24-category. (Docket No. A–98–20, IV–D– hour standard but by the combination of the O3 proposal and final decision11, IV–D–17, IV–D–19, IV–G–21). We the two standards working in concert. notices.are not adding a category below the b. PM2.5 sub-index. We received a Indeed, the annual PM2.5 level of 15 µg/level of the standard as discussed in number of comments regarding the m3 was intended to serve as thesection II.B.1. above. However, to be PM2.5 sub-index, almost all of them principal vehicle for protection againstsomewhat more precautionary, we have focusing on our proposal to set the short-term PM2.5 exposures (by reducingexpanded the ‘‘moderate’’ range by index value of 100 at the level of the 24- the entire distribution of PM2.5reducing the lower bound of this hour standard (65 µg/m3). Some concentrations in an area), with thecategory from 0.070 ppm to 0.065 ppm commenters recommended setting an short-term standard serving essentiallyO3, 8-hour average. We believe that index value of 100, or otherwise to provide supplemental protection insetting the breakpoint between the providing for cautionary messages, at special situations. 9 Given the respective‘‘good’’ and ‘‘moderate’’ categories at concentrations lower than 65 µg/m3. roles of the two standards, setting thethis lower level, is appropriate, based in One commenter, for example, stated that AQI value of 100 at the level of the 24-part on risk estimates done in under the proposal ‘‘many areas of the hour standard would not reflect theconjunction with the review of the O3 country will likely violate the annual short-term health risks associated withNAAQS which suggested that risk to standard of 15 µg/m3 without ever (or lower concentrations, which the annualhealthy people likely becomes hardly ever) reaching a PSI of 100 or a standard was designed to address.negligible at this level (Whitfield et al., category indicating some degree of Accordingly, we agree that it is1996). This change is also responsive to unhealthfulness. This situation will appropriate to caution members ofcomments from State agencies that the result in an inconsistent and sensitive groups below the level of theproposed range of the ‘‘moderate’’ inappropriate message to the public, 24-hour standard and believe thiscategory was so narrow (spanning only especially given the severe health effects should be done in a way that reflects the15 ppb O3, as compared to 20 ppb range associated with fine particles.’’ (Docket intended roles of both standards inused in the Ozone Map in 1998) that it No. A–98–20, IV–D–11). protecting against short-term risks.would be more difficult to forecast In light of these comments, we have It would also be inappropriate toaccurately and also would provide too reexamined the basis for selecting PM2.5 compare daily air-quality concentrationsquick a transition from good to AQI breakpoints and agree that the sub- directly with the level of the annualunhealthy. (Docket No. A–98–20, IV–D– index as proposed would not adequately standard (by setting the AQI value of10, IV–G–04). Conversely, an industry caution sensitive groups about potential 100 at that level), because the annualgroup and a State commenter took risks associated with short-term standard represents an average of manyexception to issuing a ‘‘limited health exposures to PM2.5. This is essentially daily concentrations rather than dailynotice’’ for O3 that we proposed as the because the proposed PM2.5 sub-index values per se. In the circumstances, wepurpose of the ‘‘moderate’’ category. was developed using the Agency’s believe the guiding principle for PM2.5(Docket No. A–98–20, IV–D–12, IV–G– historical approach to selecting index should be to set the AQI value of 10014). The State commenter objected to breakpoints, which on examination does in a way that, at least conceptually,the use of the term ‘‘health notice’’ not correspond well with the way the reflects the general level of healthbelow the level of the standard because PM2.5 standards were intended to protection against short-term risksit implies that the standard is not function. The historical practice hasprotective of public health. In addition been simply to set the AQI value of 100 8 See 63 FR 67819, 67829 (Dec. 9, 1998).to stating that the ‘‘limited health at the level of the short-term standard 9 See 62 FR 38669–71, 38676–77 (July 18, 1997).

15. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42543provided by the annual and 24-hour serve as the primary vehicle for relationship, is consistent with thestandards in combination. This protection against such concentrations. health effects evidence that was theapproach, although inexact, is As with other AQI breakpoints, it also basis for the PM standards.consistent with the historical approach, has no effect on the degree of control C. What Are the Final Revisions?in that the underlying logic of that required of specific sources.approach, as applied to a typical suite In short, EPA’s decision to treat the The sub-sections below onlyof standards, is also to set the AQI value annual standard as the principal vehicle summarize changes to the regulatoryof 100 in a way that reflects the level of for protecting against short-term PM2.5 text. They do not describe all aspects ofprotection provided against short-term concentrations, although judged to be 40 CFR part 58.50 or appendix G.risks—that is, by setting it at the level the best approach based on the available 1. What Are the General Changes?of the short-term standard that provides health information, does present athe protection. In the case of PM2.5, as different situation than that involved in Based on the proposed structure ofindicated above, the level of the 24-hour previous AQI rulemakings. As discussed the AQI, the comments we received andstandard (65 µg/m3) is too high to reflect in the preamble to the final standards, our responses to them, as discussedthe intended level of protection, and the the annual standard was intended to above, we are adopting the followinglevel of the annual standard (15 µg/m3) reduce all PM2.5 concentrations, changes to the general structure andis too low. Between the two values, the including short-term peaks, in an area reporting requirements to the AQI.available health studies indicate a a. Categories and related descriptors, sufficiently to protect public health withcontinuum of risks associated with index values and colors. We are an adequate margin of safety, aside fromincreasing PM concentrations, although adopting the index values, descriptors special situations which the 24-hourwith significant uncertainties as to the and associated colors listed in Table 1 standard was designed to address. Asextent of the risk associated with single above. one commenter suggested, however, it b. Reporting requirements. We arepeak exposures.10 Consistent with EPA’s would be possible for an area to violategeneral practice of setting AQI revising 40 CFR 58.50 to require the annual standard without ever reporting of the AQI in all MSAs withbreakpoints in symmetrical fashion experiencing (or seldom experiencing)where health effects information does a population over 350,000. In appendix daily peaks that exceeded the level of G, we are adopting roundingnot suggest particular levels,11 we the 24-hour standard. Moreover, itconcluded that it is appropriate to set conventions to be used to calculate might be difficult, if not impossible, to index values that are consistent with thethe AQI value of 100 at the mid-point predict in advance whether the annualof the range between the annual and the rounding conventions used in defining standard will be attained in a given area. the NAAQS for each pollutant.24-hour PM2.5 standards (40 µg/m3). For these reasons, as well as theGiven that decision, we also concluded The final rule retains the uncertainties in the available health requirements to identify the area forthat it is appropriate to retain the level information, it is inherently difficult toof the annual standard for an AQI value which the AQI is being reported, the judge the significance of single peak time period covered by the report, theof 50, as proposed, and to set the AQI concentrations when they occur. Inlevel of 150 at the level of the 24-hour ‘‘critical’’ pollutant for which the view of the various uncertainties reported AQI value was derived, thestandard. involved, particularly sensitive To reiterate, the purpose of setting the AQI value, and the associated category individuals may wish to avoid exposure descriptor. The final rule adds twoAQI value of 100 somewhat below the to such concentrations, especiallylevel of the 24-hour standard was to requirements: (1) To report the concentrations that approach the level associated category color if a colorreflect the dual role of the annual and of the 24-hour standard. To facilitate24-hour PM2.5 standards in protecting format is used and, (2) to report the such choices, consistent with the pollutant-specific sensitive group foragainst short-term risks, and the aim purposes of the AQI and the advice ofwas to select a breakpoint that would any reported index value greater than CASAC, we believe that cautioning 100. The final rule encourages, but doesserve as a rough surrogate for the members of sensitive groups in thegeneral level of protection provided by not require, that AQI reports include: range of 40 to 65 µg/m3 is appropriate. appropriate health effects andthe two standards in combination. We did not receive any comments onGiven the nature of the standards and cautionary statements, all AQI values the proposal to establish a concentration greater than 100, the AQI for sub-the available health information, a more of 500 µg/m3 to be associated with aexact approach was not possible. In this divisions of the MSA (if there are PM2.5 index value of 500, or our method important differences in air qualityregard, setting the breakpoint at the of selecting the intermediatemid-point of the range between the across sub-divisions of the MSA), breakpoints. Therefore, we are adopting possible causes for high index values,annual and 24-hour standards, as 500 µg/m3 as the upper bound of theopposed to a level somewhat higher or and the actual pollutant concentrations. index.12 For intermediate breakpoints in In the case of rural or small urbanlower within that range, simply the AQI between values of 150 and 500, areas that are significantly affected byreflected EPA’s general practice of we have adopted PM2.5 concentrations pollutants transported from a MSAsetting symmetrical breakpoints as that generally reflect a linear where the AQI is reported, the final ruleindicated above, and does not imply any relationship between increasing index recommends that the MSA report thesort of health-effects threshold. In values and increasing PM2.5 values. As AQI for the affected areas as well. Inparticular, it does not reflect a judgment discussed in the proposal, the generally addition, when the AQI is greater thanabout the extent of the risk associated linear relationship between AQI values 100, reporting agencies should expandwith single peak concentrations of and PM2.5 concentrations in this range, AQI reporting to include all major newsPM2.5, as to which the available health rounded to increments of 50 µg/m3 to media. The final rule continues to allowinformation is inconclusive, or the level reflect the approximate nature of such a agencies to discontinue reporting forat which EPA might set a 24-hourstandard if the annual standard did not 12 As discussed in the proposal, should the final any pollutant, if index values for that SHL for PM2.5, when promulgated, be different from pollutant have been below 50 for an 10 See 62 FR 38670, 38677 (July 18, 1997). this concentration, we will revise this PM2.5 sub- entire season or a year. However, if in 11 See 63 FR 67824, 67832 (Dec. 9, 1998). index accordingly. subsequent years pollutant levels rise

16. 42544 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulationssuch that index values for that pollutant c. Index name. We are adopting the corresponding to the 8-hour O3 standardwould be above 50, then the final rule name the Air Quality Index or AQI. and the PM2.5 standards, as well asrequires that AQI reporting for that conforming changes to the CO, 1-hour 2. What Are the Changes to the Sub-pollutant resume. The final rule O3, PM10, and SO2 sub-indices. The Indices?emphasizes the importance of adopted breakpoints for the O3 (8-hourforecasting the AQI by specifying that Based on the proposed sub-indices, and 1-hour) PM2.5, PM10, CO and SO2forecasted values should be reported, the comments we received and our sub-indices are listed in Table 3.when possible, but does not require that responses to them, as discussed above,forecasted values be reported. we are adopting new sub-indices TABLE 3.—BREAKPOINTS FOR O3, PM2.5, PM10, CO, AND SO2 SUB-INDICES O3 PM AQI value PM2.5, 24-hr PM10, 24-hr CO, 8-hr (ppm) SO2, 24-hr (ppm) 8-hr (ppm) 1-hr (ppm) (µg/m3) (µg/m3)50 ................ 0.06 ............. ................................. 15 50 4 0.03100 .............. 0.08 ............. 0.12 40 150 9 0.14150 .............. 0.10 ............. 0.16 65 250 12 0.22200 .............. 0.12 ............. 0.20 * 150 350 15 0.30300 .............. 0.40 (1-hr) ... 0.40 * 250 420 30 0.60400 .............. 0.50 (1-hr) ... 0.50 * 350 500 40 0.80500 .............. 0.60 (1-hr) ... 0.60 * 500 600 50 1.00 * If a different SHL for PM2.5 is promulgated, these numbers will be revised accordingly. These sub-indices are presented in brochure), with final revisions to the general information about O3.more detail in appendix G to reflect the AQI, and will identify sensitive groups Information about ground-level aschanges to the numerical rounding in the health effects statements for each contrasted to stratospheric O3 may beconventions for calculating index of the pollutants, and include the found in EPA’s publication ‘‘Ozone:values. pollutant-specific health effects and Good Up High, Bad Nearby.’’ The EPA’s cautionary statements discussed above. video, ‘‘Ozone Double Trouble’’ alsoD. What Are the Related Informational A colorful fact sheet, called the ‘‘Air provides information about ground-levelMaterials? Quality Guide,’’ provides information and stratospheric O3 and the health The primary documents associated about the AQI, O3 health effects and the effects associated with exposure towith the AQI and this rulemaking, are sources of ground-level O3 is available ground-level O3, or smog.our guidance on AQI reporting, on the AIRNOW web site. A revised In addition to the products discussed‘‘Guideline for Public Reporting of Daily booklet, ‘‘SMOG—Who Does It Hurt?,’’ above, to address the concerns ofAir Quality—Air Quality Index (AQI)’’ provides information for the general commenters that when air quality is in(EPA 1999a), and our guidance on AQI public about O3 health effects and is the ‘‘unhealthy for sensitive groups’’forecasting, ‘‘Guideline for Developing based on scientific information gained range the public will not understandan Ozone Forecasting Program’’ (EPA in the recent review of the O3 standard. that the standard has been exceeded or1999b). These documents are available ‘‘SMOG—Who Does It Hurt?’’ was who is at risk, we are going toon AIRLINKS (http://www.epa.gov/ designed to provide, in simple language, significantly increase education andairlinks). The AQI Reporting document enough detail for individuals to outreach related to the AQI. At thiscontains information regarding the AQI understand who is at most risk from O3 point, we are still in the process ofrequirements and recommendations, exposure and why, the nature of O3 planning specific new products orexample AQI reports, and a list of MSAs health effects, and a detailed activities, but have decided whatrequired to report the AQI. It also explanation of how individuals can general direction these efforts will take.includes pollutant-specific health reduce the likelihood of exposure using First, we plan to increase our contactseffects and cautionary statements for use common everyday activities as with the news providers to better informwith the index, for O3, PM2.5, PM10, CO, examples. We are also developing a them about the importance of includingand SO2. The AQI Forecasting shorter, summary pamphlet about O3 accurate, timely and understandabledocument explains the steps necessary health effects to complement the information in their broadcasts andto start an air pollution forecasting ‘‘SMOG—Who Does It Hurt?’’ booklet. reporting, and to enlist them as fullprogram. Included in the document is We expect the AQI brochure, ‘‘SMOG— partners in the implementation of theguidance on using hourly O3 Who Does It Hurt?’’ and the shorter AQI. Second, we plan to form newconcentrations as predictors for 8-hour summary pamphlet about O3 health associations with health care providersaverages. effects to be available in paper format to keep them informed about air Other related informational materials and on the AIRNOW web site early in pollution health effects, since theseare also available. The brochure ‘‘The the 1999 ozone season. In addition, we professionals are the most trustedPollutant Standards Index’’ (EPA 1994) will translate the Air Quality Guide, the source of health effects information.contained general information about the AQI brochure, ‘‘SMOG—Who Does It Third, we plan to increase directhealth effects and air quality, and Hurt?’’, and the shorter summary outreach to the public through a varietygeneral precautions that sensitive pamphlet into Spanish. These materials of means, including materials tailored togroups and the general public can take will be available on a Spanish page on school-age children, the Spanish-to avoid exposures of concern. It is the AIRNOW web site. speaking community, and others.being revised to be consistent with the There are other materials available on Finally, we plan to work with publicnew name (i.e., the Air Quality Index the AIRNOW web site that provide health interest organizations to support

17. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42545their efforts to provide more immediate U.S.C. 605(b), this requirement may be section 203 of the UMRA, EPA hasand interactive education and outreach waived if EPA certifies that the rule will determined that this rule contains noto all of these groups. not have a significant economic impact regulatory requirements that might on a substantial number of small significantly or uniquely affect smallIII. Regulatory and Environmental entities. Small entities include small governments. This rule requiresImpact Analyses businesses, small not-for-profit reporting of the Air Quality Index onlyA. Executive Order 12866: OMB Review enterprises, and governmental entities in MSAs with populations greater thanof ‘‘Significant Actions’’ with jurisdiction over populations less 350,000, and therefore does not affect than 50,000 people. small governments. Under Executive Order 12866, the Today’s final decision to revise theAgency must determine whether a AQI program modifies existing air D. Paperwork Reduction Actregulatory action is ‘‘significant’’ and, quality reporting requirements for Today’s final decision does nottherefore, subject to Office of MSA’s with populations over 350,000 establish any new informationManagement and Budget (OMB) review people. Today’s final decision will not collection requirements beyond thoseand the requirements of the Executive establish any new regulatory which are currently required under theOrder. The order defines ‘‘significant requirements affecting small entities. On Ambient Air Quality Surveillanceregulatory action’’ as one that may: the basis of the above considerations, Regulations in 40 CFR part 58 (OMB (1) Have an annual effect on the EPA certifies that today’s final decision #2060–0084, EPA ICR No. 0940.15).economy of $100 million or more or will not have a significant economic Therefore, the requirements of theadversely affect in a material way the impact on a substantial number of small Paperwork Reduction Act do not applyeconomy, a sector of the economy, entities within the meaning of the RFA. to today’s action.productivity, competition, jobs, the Based on the same considerations, EPAenvironment, public health or safety, or E. Executive Order 13045: Children’s also certifies that the new small-entity HealthState, local, or tribal governments or provisions in section 244 of the Smallcommunities; Business Regulatory Enforcement Executive Order 13045, entitled (2) Create a serious inconsistency or Fairness Act (SBREFA) do not apply. ‘‘Protection of Children fromotherwise interfere with an action taken Environmental Health Risks and Safetyor planned by another Agency; C. Unfunded Mandates Reform Act Risks’’ (62 FR 19885, April 23, 1997), (3) Materially alter the budgetary Title II of the Unfunded Mandates requires Federal agencies to ensure thatimpact of entitlements, grants, user fees, Reform Act of 1995 (UMRA), Public their policies, programs, activities, andor loan programs or the rights and Law 104–4, establishes requirements for standards identify and assessobligations or recipients thereof; or Federal agencies to assess the effects of environmental health and safety risks (4) Raise novel legal or policy issues their regulatory actions on State, local, that may disproportionately affectarising out of legal mandates, the and tribal governments and the private children. To respond to this order,President’s priorities, or the principles sector. Under section 202 of the UMRA, agencies must explain why theset forth in the Executive Order. The EPA generally must prepare a written regulation is preferable to otherEPA has determined that the revisions statement, including a cost-benefit potentially effective and reasonablyto air quality index reporting in this analysis, for proposed and final rules feasible alternatives considered by thefinal rule would not have an annual with ‘‘Federal mandates’’ that may agency. In today’s final decision, EPAeffect on the economy of $100 million result in expenditures to State, local and identified children as one of theor more or adversely affect in a material tribal governments, in the aggregate, or sensitive groups which may be atway the economy, a sector of the to the private sector, of $100 million or increased risk of experiencing theeconomy, productivity, competition, more in any 1 year. In addition, before effects of concern following exposure tojobs, the environment, public health or EPA establishes any regulatory O3, PM2.5 and NO2.5. The AQI categories,safety, or State, local, or tribal requirements that may significantly or descriptors, and health effects andgovernments or communities, and uniquely affect small governments, cautionary statements as proposed, fortherefore did not prepare a regulatory including tribal governments, it must the first time reflect consideration of theimpact assessment. The OMB has have developed under section 203 of the increased health risk to children whichadvised us this final decision should be UMRA a small government agency plan. may result from such exposures.construed as a ‘‘significant regulatory The plan must provide for notifying Promulgation of the proposed AQI isaction’’ within the meaning of Executive potentially affected small governments, one potentially effective alternative thatOrder 12866. Accordingly, this action enabling officials of affected small was considered. However, based onwas submitted to the OMB for review. governments to have meaningful and comments that the public may not beAny changes made in response to OMB timely input in the development of EPA aware that healthy, active children aresuggestions or recommendations will be regulatory proposals with significant included in the sensitive groups for O3,documented in the public record and Federal intergovernmental mandates, PM2.5 and NO2, we have adopted themade available for public inspection at and informing, educating, and advising additional requirement that reportingEPA’s Air and Radiation Docket small governments on compliance with agencies must include a pollutant-Information Center (Docket No. A–98– the regulatory requirements. specific statement of the sensitive20). The EPA has determined that today’s groups when an index value of 100 is final decision would not include a exceeded. For example, when reportingB. Regulatory Flexibility Analysis/Small Federal mandate that may result in an AQI value of 110 for ozone, theBusiness Regulatory Enforcement estimated costs of $100 million in any reporting agency must include aFairness Act 1 year to either State, local, or tribal statement that children and people with Under the Regulatory Flexibility Act governments, in the aggregate, or to the asthma are the groups most at risk.(RFA), 5 U.S.C. 601 et seq., EPA must private sector. Accordingly, EPA has Whenever the AQI value is above 100prepare a regulatory flexibility analysis determined that the provisions of for a pollutant, and children are one ofassessing the impact of any proposed or section 202 of the UMRA do not apply the sensitive groups for that pollutant,final rule on small entities. Under 6 to this rulemaking. With regard to the AQI report must include a statement

18. 42546 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulationsthat children are at risk. Therefore, This rule does not establish a wholly uniquely affect communities of Indiantoday’s action does comply with the new requirement but rather modifies tribal governments. To the extent thatrequirements of E.O. 13045. existing reporting requirements which air pollution from upwind MSAs State and local governments have been significantly affects any lands withinF. Executive Order 12848: implementing for approximately 20 Indian country, this impact is not aEnvironmental Justice years. While these changes are result of, or affected by, today’s rule and Executive Order 12848 requires that significant in many ways, they are not would be addressed under existingeach Federal agency make achieving expected to result in a significant requirements governing theenvironmental justice part of its mission increase in reporting burdens. implementation of air quality standards.by identifying and addressing, as Nonetheless, EPA engaged in extensiveappropriate, disproportionately high consultation with State and local I. National Technology Transfer andand adverse human health or governments in the development of the Advancement Actenvironmental effects of its programs, proposed and final rules, and this Section 12(d) of the Nationalpolicies, and activities on minorities consultation is discussed and Technology Transfer and Advancementand low-income populations in the documented elsewhere in today’s notice Act of 1995 (NTTAA), Public Law 104–United States. and in the notice of proposed The nature of today’s action is to 113, section 12(d) (15 U.S.C. 272 note) rulemaking. directs EPA to use voluntary consensusinform the general public, includingminorities and low-income populations, H. Executive Order 13084: Consultation standards in its regulatory activitiesabout the nature of the air pollution in and Coordination With Indian Tribal unless to do so would be inconsistentthe areas in which they live. Today’s Governments with applicable law or otherwiseaction establishes a uniform tool for Under Executive Order 13084, EPA impractical. Voluntary consensusStates to use to develop programs which may not issue a regulation that is not standards are technical standards (e.g.,will caution particularly sensitive required by statute, that significantly or materials specifications, test methods,people to minimize their exposures and uniquely affects the communities of sampling procedures, and businesseducate the public about general health Indian tribal governments, and that practices) that are developed or adoptedeffects associated with exposure to imposes substantial direct compliance by voluntary consensus standardsdifferent pollution levels. States may costs on those communities, unless the bodies. The NTTAA directs EPA toalso use information established as part Federal government provides the funds provide Congress, through OMB,of the AQI to trigger programs designed necessary to pay the direct compliance explanations when the Agency decidesto reduce emissions to avoid costs incurred by the tribal not to use available and applicableexceedances of the NAAQS. Therefore, governments, or EPA will consult with voluntary consensus standards. Thistoday’s action will help facilitate public those governments. If EPA complies by action does not involve technicalparticipation, outreach, and consulting, Executive Order 13084 standards. Therefore, EPA did notcommunication in areas where requires us to provide to OMB, in a consider the use of any voluntaryenvironmental justice issues are present. separately identified section of the consensus standards. preamble to the rule, a description of J. Congressional Review ActG. Executive Order 12875: Enhancing the extent of our prior consultation withIntergovernmental Partnerships The Congressional Review Act, 5 representatives of affected tribal Under Executive Order 12875, EPA governments, a summary of the nature U.S.C. 801 et seq., as added by the Smallmay not issue a regulation that is not of their concerns, and a statement Business Regulatory Enforcementrequired by statute and that creates a supporting the need to issue the Fairness Act of 1996, generally providesmandate upon a State, local or tribal regulation. In addition, Executive Order that before a rule may take effect, thegovernment, unless the Federal 13084 requires us to develop an agency promulgating the rule mustgovernment provides the funds effective process permitting elected submit a rule report, which includes anecessary to pay the direct compliance officials and other representatives of copy of the rule, to each House of thecosts incurred by those governments, or Indian tribal governments ‘‘to provide Congress and to the Comptroller Generalwe will consult with those governments. meaningful and timely input in the of the United States. The EPA willIf EPA complies by consulting, development of regulatory policies on submit a report containing this rule andExecutive Order 12875 requires us to matters that significantly or uniquely other required information to the U.S.provide to OMB a description of the affect their communities.’’ Senate, the U.S. House ofextent of our prior consultation with Today’s rule implements Representatives, and the Comptrollerrepresentatives of affected State, local requirements specifically set forth by General of the United States prior to theand tribal governments, the nature of the Congress in section 319 of the Act publication of the rule in the Federaltheir concerns, copies of any written without the exercise of any discretion Register. This rule is not a ‘‘major rule’’communications from the governments, by us. Accordingly, the requirements of as defined by 5 U.S.C. 804(2).and a statement supporting the need to section 3(b) of Executive Order 13084issue the regulation. In addition, do not apply to this rule. IV. ReferencesExecutive Order 12875 requires us to This rule governs the reporting of air CEQ, (1976) A Recommended Air Pollutiondevelop an effective process permitting quality by States for MSAs and, in some Index, report prepared by the Federalelected officials and other cases, areas that are significantly Interagency Task Force on Air Qualityrepresentatives of State, local and tribal affected by transport of pollutants from Indicators, Council on Environmentalgovernments ‘‘to provide meaningful MSAs. In extensive public and Quality, Environmental Protection intergovermental coordination efforts Agency, and Department of Commerce.and timely input in the development of EPA, (1994) Measuring Air Quality: Theregulatory proposals containing during the development of the proposal, Pollutant Standards Index, U.S.significant unfunded mandates.’’ EPA received no information which Environmental Protection Agency, Office Today’s rule implements would suggest that the rule will impose of Air Quality Planning and Standardsrequirements set forth in section 319 of new requirements on Indian tribal (MD–10), Research Triangle Park, NC,the Act and thus is required by statute. governments nor will it significantly or 27711, EPA 451/K–94–001.

19. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42547EPA, (1999a) Guideline for Public Reporting 2. Section 58.50 is revised to read as 2. Why Report the AQI? of Daily Air Quality—Air Quality Index follows: The AQI offers various advantages: (AQI), U.S. Environmental Protection a. It is simple to create and understand. Agency, Office of Air Quality Planning § 58.50 Index reporting. b. It conveys the health implications of air and Standards, Research Triangle Park, (a) The State shall report to the NC, 27711, EPA–454/R–99–010. quality.EPA, (1999b) Guideline for Developing an general public through prominent notice c. It promotes uniform use throughout the Ozone Forecasting Program, U.S. an air quality index in accordance with country. Environmental Protection Agency, Office the requirements of appendix G to this 3. Must I Report the AQI? of Air Quality Planning and Standards, part. Research Triangle Park, NC, 27711, EPA– (b) Reporting is required by all You must report the AQI daily if yours is 454/R–99–009. Metropolitan Statistical Areas with a a metropolitan statistical area (MSA) with aEPA, (1999c) The Air Quality Index, U.S. population exceeding 350,000. population over 350,000. Environmental Protection Agency, Office (c) The population of a Metropolitan 4. What Goes Into My AQI Report? of Air Quality Planning and Standards, Statistical Area for purposes of index i. Your AQI report must contain the Research Triangle Park, NC, 27711, in preparation. reporting is the most recent decennial following:Science Applications International U.S. census population. a. The reporting area(s) (the MSA or Corporation, (1998) Report of Eight 3. Appendix G to part 58 is revised to subdivision of the MSA). Focus Groups on the Ozone Map, the read as follows: b. The reporting period (the day for which Pollutant Standards Sub-index for the AQI is reported). Ozone, and the Ozone Health Effects Appendix G to Part 58—Uniform Air c. The critical pollutant (the pollutant with Booklet, Science Applications Quality Index (AQI) and Daily the highest index value). International Corporation, McLean, VA. Reporting d. The AQI (the highest index value).U.S. Department of Commerce, (1998) General Requirements e. The category descriptor and index value Statistical Abstract of the United States, 1. What is the AQI? associated with the AQI and, if you choose U.S. Bureau of the Census.Whitfield, R.G.; Biller, W.F.; Jusko, M.J.; 2. Why report the AQI? to report in a color format, the associated Keisler, JM (1996) A probabilistic 3. Must I report the AQI? color. Use only the following descriptors and assessment of health risks associated 4. What goes into my AQI report? colors for the six AQI categories: with short-term exposure to tropospheric 5. Is my AQI report for my MSA only? ozone. Report prepared for U.S. EPA, 6. How do I get my AQI report to the TABLE 1.—AQI CATEGORIES OAQPS. Argonne National Laboratory; public? Argonne, IL. 7. How often must I report the AQI? Use this And thisWolff, G.T., (1995) Letter from Chairman of 8. May I make exceptions to these reporting For this AQI descriptor color 1 the Clean Air Scientific Advisory requirements? Committee to the EPA Administrator, Calculation 0 to 50 .............. ‘‘Good’’ ............. Green. dated November 30, 1995. EPA–SAB– CASAC–LTR–96–002. 9. How does the AQI relate to air pollution 51 to 100 .......... ‘‘Moderate’’ ....... Yellow. levels?List of Subjects in 40 CFR Part 58 10. Where do I get the pollutant 101 to 150 ........ ‘‘Unhealthy for Orange. Environmental protection, Air concentrations to calculate the AQI? Sensitive 11. Do I have to forecast the AQI? Groups’’.pollution control, Intergovernmental 12. How do I calculate the AQI?relations, Reporting and recordkeeping Background and Reference Materials 151 to 200 ........ ‘‘Unhealthy’’ ...... Red.requirements. Dated: July 23, 1999. 13. What additional information should I 201 to 300 ........ ‘‘Very Purple. know? Unhealthy’’.Carol M. Browner,Administrator. General Requirements 301 and above ‘‘Hazardous’’ .... Ma- Accordingly, 40 CFR part 58 is 1. What Is the AQI? roon.1amended as follows: The AQI is a tool that simplifies reporting 1 Specific colors can be found in the most air quality to the general public. The AQIPART 58—AMBIENT AIR QUALITY recent reporting guidance (Guideline for Public incorporates into a single index Reporting of Daily Air Quality—Air QualitySURVEILLANCE concentrations of 5 criteria pollutants: ozone Index (AQI)). (O3), particulate matter (PM), carbon 1. The authority citation for part 58 f. The pollutant specific sensitive groups monoxide (CO), sulfur dioxide (SO2), andcontinues to read as follows: nitrogen dioxide (NO2). The scale of the for any reported index value greater than 100. Authority: 42 U.S.C. 7410, 7601(a), 7613, index is divided into general categories that Use the following sensitive groups for eachand 7619. are associated with health messages. pollutant: When this pollutant has an index value above 100 * * * Report these sensitive groups * * *Ozone ....................................................................................................... Children and people with asthma are the groups most at risk.PM2.5 ......................................................................................................... People with respiratory or heart disease, the elderly and children are the groups most at risk.PM10 .......................................................................................................... People with respiratory disease are the group most at risk.CO ............................................................................................................. People with heart disease are the group most at risk.SO2 ........................................................................................................... People with asthma are the group most at risk.

20. 42548 Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations When this pollutant has an index value above 100 * * * Report these sensitive groups * * *NO2 ........................................................................................................... Children and people with respiratory disease are the groups most at risk. ii. When appropriate, your AQI report may ii. If all index values remain below 50 for Monitoring Station (SLAMS) or parts of thealso contain the following: a year, then you may report the AQI at your SLAMS required under 40 CFR 58.20 for a. Appropriate health and cautionary discretion. In subsequent years, if pollutant each pollutant except PM. For PM, you needstatements. levels rise to where the AQI would be above only calculate and report the AQI on days for b. The name and index value for other 50, then the AQI must be reported as which you have measured air quality datapollutants, particularly those with an index required in sections 3, 4, 6, and 7 of this (e.g., particulate monitors often report valuesvalue greater than 100. appendix. only every sixth day). You may use c. The index values for sub-areas of your Calculation particulate measurements from monitors thatMSA. are not reference or equivalent methods (for d. Causes for unusual AQI values. 9. How Does the AQI Relate to Air Pollution example, continuous PM10 or PM2.5 monitors) e. Actual pollutant concentrations. Levels? if you can relate these measurements by5. Is My AQI Report for My MSA Only? For each pollutant, the AQI transforms statistical linear regression to reference or ambient concentrations to a scale from 0 to equivalent method measurements. Generally, your AQI report applies to your 500. The AQI is keyed as appropriate to theMSA only. However, if a significant air national ambient air quality standards 11. Do I Have to Forecast the AQI?quality problem exists (AQI greater than 100) (NAAQS) for each pollutant. In most cases, You should forecast the AQI to providein areas significantly impacted by your MSA the index value of 100 is associated with the timely air quality information to the public,but not in it (for example, O3 concentrations numerical level of the short-term standard but this is not required. If you choose toare often highest downwind and outside an (i.e., averaging time of 24-hours or less) for forecast the AQI, then you may consider bothurban area), you should identify these areas each pollutant. Different approaches are long-term and short-term forecasts. You canand report the AQI for these areas as well. taken for NO2, for which no short-term forecast the AQI at least 24-hours in advance6. How Do I Get My AQI Report to the Public? standard has been established, and for PM2.5, using the most accurate and reasonable for which the annual standard is the procedures considering meteorology, You must furnish the daily report to the principal vehicle for protecting against short-appropriate news media (radio, television, topography, availability of data, and term concentrations. The index value of 50and newspapers). You must make the daily forecasting expertise. The document is associated with the numerical level of thereport publicly available at one or more ‘‘Guideline for Developing an Ozone annual standard for a pollutant, if there isplaces of public access, or by any other Forecasting Program’’ (the Forecasting one, at one-half the level of the short-termmeans, including a recorded phone message, standard for the pollutant, or at the level at Guidance) will help you start a forecastinga public Internet site, or facsimile which it is appropriate to begin to provide program. You can also issue short-termtransmission. When the AQI value is greater guidance on cautionary language. Higher forecasts by predicting 8-hour ozone valuesthan 100, it is particularly critical that the categories of the index are based on from 1-hour ozone values using methodsreporting to the various news media be as increasingly serious health effects and suggested in the Reporting Guidance,extensive as possible. At a minimum, it increasing proportions of the population that ‘‘Guideline for Public Reporting of Daily Airshould include notification to the media with are likely to be affected. The index is related Quality.’’the largest market coverages for the area in to other air pollution concentrations through 12. How Do I Calculate the AQI?question. linear interpolation based on these levels. The AQI is equal to the highest of the i. The AQI is the highest value calculated7. How Often Must I Report the AQI? numbers corresponding to each pollutant. for each pollutant as follows: You must report the AQI at least 5 days per For the purposes of reporting the AQI, the a. Identify the highest concentration amongweek. Exceptions to this requirement are in sub-indexes for PM10 and PM2.5 are to be all of the monitors within each reporting areasection 8 of this appendix. considered separately. The pollutant and truncate the pollutant concentration to responsible for the highest index value (the one more than the significant digits used to8. May I Make Exceptions to These Reporting express the level of the NAAQS for that reported AQI) is called the ‘‘critical’’Requirements? pollutant. This is equivalent to the rounding pollutant. i. If the index value for a particular conventions used in the NAAQS.pollutant remains below 50 for a season or 10. Where Do I Get the Pollutant b. Using Table 2, find the two breakpointsyear, then you may exclude the pollutant Concentrations To Calculate the AQI? that contain the concentration.from your calculation of the AQI in section You must use concentration data from c. Using Equation 1, calculate the index.12. population-oriented State/Local Air d. Round the index to the nearest integer. TABLE 2.—BREAKPOINTS FOR THE AQI These breakpoints Equal these AQIs * * * Category O3 (ppm) O3 (ppm) PM2.5 PM10 CO (ppm) SO2 (ppm) 8-hour 1-hour 1 (µg/m3) (µg/m3) NO2 (ppm) AQI0.000–0.064 ............. ...................... 0.0–15.4 0–54 0.0–4.4 0.000–0.034 (2) 0–50 Good.0.065–0.084 ............. ...................... 15.5–40.4 55–154 4.5–9.4 0.035–0.144 (2) 51–100 Moderate.0.085–0.104 ............. 0.125–0.164 40.5–65.4 155–254 9.5–12.4 0.145–0.224 (2) 101–150 Unhealthy for sensitive groups.0.105–0.124 ............. 0.165–0.204 4 65.5–150.4 255–354 12.5–15.4 0.225–0.304 (2) 151–200 Unhealthy.0.125–0.374 ............. 0.205–0.404 4 150.5–250.4 355–424 15.5–30.4 0.305–0.604 0.65–1.24 201–300 Very unhealthy.( 3 ) ............................ 0.405–0.504 4 250.5–350.4 425–504 30.5–40.4 0.605–0.804 1.25–1.64 301–400( 3 ) ............................ 0.505–0.604 4 350.5–500.4 505–604 40.5–50.4 0.805–1.004 1.65–2.04 401–500 Hazardous. 1 Areas are generally required to report the AQI based on 8-hour ozone values. However, there are a small number of areas where an AQIbased on 1-hour ozone values would be more precautionary. In these cases, in addition to calculating the 8-hour ozone index value, the 1-hourozone index value may be calculated, and the maximum of the two values reported.

21. Federal Register / Vol. 64, No. 149 / Wednesday, August 4, 1999 / Rules and Regulations 42549 2 NO 2 has no short-term NAAQS and can generate an AQI only above an AQI value of 200. 3 8-hour O values do not define higher AQI values (≥ 301). AQI values of 301 or higher are calculated with 1-hour O3 concentrations. 3 4 If a different SHL for PM 2.5 is promulgated, these numbers will change accordingly. ii. If the concentration is equal to a between two breakpoints, then calculate the footnote 1 to Table 2). In these cases, youbreakpoint, then the index is equal to the index of that pollutant with Equation 1. You may use 1-hour values as well as 8-hourcorresponding index value in Table 2. must also note that in some areas, the AQI values to calculate index values and then useHowever, Equation 1 can still be used. The based on 1-hour O3 will be more the maximum index value as the AQI for O3.results will be equal. If the concentration is precautionary than using 8-hour values (see I Hi − I Lo Ip = BPHI − BPLo ( ) C p − BPLo + I Lo (Equation 1)Where: b. Find the breakpoints for 1-hour O3 at Background and Reference MaterialsIp = the index value for pollutantp 0.156 ppm as 0.125 ppm and 0.164 ppm, corresponding to index values 101 and 150; 13. What Additional Information Should ICp = the truncated concentration of Know? pollutantp c. Find the breakpoints for 8-hour O3 atBPHi = the breakpoint that is greater than or 0.130 ppm as 0.125 ppm and 0.374 ppm, The EPA has developed a computer equal to Cp corresponding to index values 201 and 300; program to calculate the AQI for you. TheBPLo = the breakpoint that is less than or d. Apply Equation 1 for 210 µg/m3, PM10: program works with Windows 95, it prompts equal to Cp for inputs, and it displays all the pertinent 150 − 101IHi = the AQI value corresponding to BPHi (210 − 155) + 101 = 128. information for the AQI (the index value,Ilo = the AQI value corresponding to BPLo. 254 − 155 color, category, sensitive group, health iii. If the concentration is larger than the e. Apply Equation 1 for 0.156 ppm, 1-hour effects, and cautionary language). The EPAhighest breakpoint in Table 2 then you may O3: has also prepared a brochure on the AQI thatuse the last two breakpoints in Table 2 when explains the index in detail (The Air Qualityyou apply Equation 1. 150 − 101 Index), Reporting Guidance (Guideline for (0.156 − 0.125) + 101 = 140 Public Reporting of Daily Air Quality) thatExample 0.164 − 0.125 iv. Using Table 2 and Equation 1, calculate provides associated health effects and f. Apply Equation 1 for 0.130 ppm, 8-hourthe index value for each of the pollutants cautionary statements, and Forecasting O3:measured and select the one that produces Guidance (Guideline for Developing anthe highest index value for the AQI. For 300 − 201 Ozone Forecasting Program) that explains theexample, if you observe a PM10 value of 210 (0.130 − 0.125) + 201 = 203 steps necessary to start an air pollutionµg/m3, a 1-hour O3 value of 0.156 ppm, and 0.374 − 0.125 forecasting program. You can download thean 8-hour O3 value of 0.130 ppm, then do g. Find the maximum, 203. This is the AQI. program and the guidance documents atthis: The minimal AQI report would read: www.epa.gov/airnow. a. Find the breakpoints for PM10 at 210 µg/ v. Today, the AQI for my city is 203 whichm3 as 155 µg/m3 and 254 µg/m3, is very unhealthy, due to ozone. Children [FR Doc. 99–19433 Filed 8–3–99; 8:45 am]corresponding to index values 101 and 150; and people with asthma are the groups most BILLING CODE 6560–50–P at risk.

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