|
TODAY'S ACTION
- The Environmental Protection Agency (EPA) is revising its Air Quality Index to enhance
the public's understanding of air pollution across the nation. Previously known as the
Pollutant Standards Index, this uniform air quality index is used by state and local
agencies for reporting on daily air quality to the public. The Index provides general
information to the public about air quality and associated health effects .
- EPA is revising the Index to update health messages for carbon monoxide, sulfur dioxide
and nitrogen dioxide. It will also reflect updated health information considered in the
Agency's recent reviews of the air quality standards for ground-level ozone (smog) and
particulate matter. The revised Index will ensure consistency between current science on
the health effects of all of these air pollutants and the reporting of this air quality and
health information to the public.
- EPA developed the revised Index in close partnership with health and public affairs
experts in state and local agencies.
WHAT ARE THE BENEFITS OF THE REVISIONS?
- Today's action enhances the public's understanding of the nation's air quality by
providing clear and consistent information regarding the health effects of
several common air pollutants.
- The revised Index provides more accurate and specific information on health risks
associated with exposure to air pollution. This, in turn, will help individuals make
informed decisions regarding actions to avoid or reduce their exposure to these pollutants.
- The revised Index can also serve as a basis for programs that encourage the public to take
action to reduce air pollution on days when levels are projected to be of concern to local
communities.
- A new national Internet website, AIRNOW, which includes "real time" air quality data
and forecasts of summertime smog levels in many states, uses the Index categories, colors
and descriptors to communicate information about air quality.
BACKGROUND
- Under the Clean Air Act, EPA is required to establish a nationally uniform air quality index for the reporting of air quality. In 1976, EPA established this index, then called the Pollutant Standards Index, for use by state and local communities across the country.
- The Index provides information on pollutant concentrations for ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. The Index is "normalized" across pollutants so that an Index value of 100 represents the level of health
protection associated with the health-based standard for each pollutant and an Index value of 500 represents the significant harm level.
- This Index has been adopted internationally and is used around the world to provide the public with information on air pollutants.
- On July 18, 1997, EPA revised the ozone and particulate matter standards, in light of a
comprehensive review of new scientific evidence. EPA replaced the 1-hour ozone
standard with an 8-hour ozone standard, and supplemented the particulate matter standard
with 24-hour and annual standards for fine particulate matter.
- The revised Index was developed through extensive coordination with public information, health, and air quality experts from state and local agencies, as well as input from the general public through EPA-sponsored focus groups. For example, EPA sponsored eight
focus groups in major U.S. cities to help evaluate how to most effectively communicate
air quality and health effects information. Numerous state and local agencies and
associations also participated through workshops to provide comment on the Index
revisions.
WHAT ARE THE SPECIFIC REVISIONS TO THE INDEX?
- EPA is changing the name of the Pollutant Standards Index to the Air Quality Index.
- The revised Index adds an additional air quality category just above the level of the
standard. Previously, Index values from 101 - 200 were characterized "unhealthful." The
revised Index establishes a category from 101 -150 characterized as "unhealthy for
sensitive groups," and a category of 151 - 200 as "unhealthy."
- When air quality is "unhealthy for sensitive groups", EPA has added a corresponding
requirement to report a pollutant-specific statement indicating what specific groups in the
population are most at risk. For example, when the Index is above 100 for ozone the AQI
report will contain the statement "Children and people with asthma are the groups most at
risk."
- To the extent that state and local agencies use colors to communicate Index values,
specific colors are required. For instance, any agency that chooses to use colors to
communicate such values must represent the Index values of 151 - 200 as "red".
Examples of the use of color in Index reporting include the color bars that appear in many
newspapers, and the color contours of the Ozone Map.
- The revised Index includes modifications to the ozone sub-index and a new sub-index for
fine particulate matter. These changes to the Index are based on health effects
information from the review of the ozone and particulate matter standards, as well as
information and feedback provided by state and local agencies and the public. The
modifications also reflect the addition of the new air quality category "unhealthy for
sensitive groups."
- The revised Index includes changes to the sub-indices for ozone, inhalable particulate
matter (PM10), carbon monoxide and sulfur dioxide to reflect the addition of the new air
quality category of "unhealthy for sensitive groups."
- This action requires all Metropolitan Statistical Areas with populations greater than 350,000 to report the Index. Previously, urbanized areas with populations greater than 200,000 were required to report.
WHO WILL BE AFFECTED BY THESE REVISIONS?
- The revised Index benefits the general public by providing clear and consistent
information regarding air quality and associated health risks.
- The revised Index will not impose new burdens on state and local agencies.
FOR MORE INFORMATION
- Interested parties can download the final decision on the Index from EPA's World Wide
Web site on the Internet under "recent actions" at the following address:
http://www.epa.gov/ttn/oarpg. For further information about the proposal, contact Susan
Stone (919 541-1146) or Terence Fitz-Simons (919 541-0889) of EPA's Office of Air Quality Planning and Standards.
- To read ozone forecasts and to see maps showing real-time ozone animations, go to the
AIRNOW web site at http://www.airnow.gov. Each day's animation is available by early
afternoon. Next-day forecasts generally are available after 4:15 p.m.
|
![[logo] US EPA](https://webarchive.library.unt.edu/eot2008/20081109013413im_/http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}