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Table 4-47: Air Pollution Trends in Selected Metropolitan Statistical Areas

(Number of days with AQI values greater than 100 at trend sites and all monitoring sites)

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Metropolitan Statistical Area All sites (R)Number of trend sites Trend sites
(R) Total number of sites in 2007 (R) Number of days with AQI > 100 (2007) (R) 1994 (R) 1995 (R) 1996 (R) 1997 (R) 1998 (R) 1999 (R) 2000 (R) 2001 (R) 2002 (R) 2003 (R) 2004 (R) 2005 (R) 2006 2007
Akron, OH 18 22 7 23 21 26 16 37 40 14 28 38 15 10 30 5 22
Albany-Schenectady-Troy, NY 26 15 5 13 12 9 8 9 15 3 18 17 9 5 8 2 13
Albuquerque, NM 74 6 17 5 3 5 2 3 5 7 1 11 15 5 9 3 1
Allentown-Bethlehem-Easton, PA 22 13 5 10 18 19 22 39 31 18 34 38 13 13 16 10 12
Atlanta, GA 59 57 19 27 53 41 46 76 85 62 39 38 23 20 28 37 34
Austin-San Marcos, TX 23 4 1 8 28 5 2 9 14 14 5 8 9 8 9 13 4
Bakersfield, CA 54 143 17 129 133 127 94 104 161 164 158 186 169 160 122 137 131
Baltimore, MD 72 45 17 61 57 43 46 70 54 39 50 59 31 31 36 34 45
Baton Rouge, LA 38 25 15 19 31 15 23 29 42 47 17 16 23 22 29 23 17
Bergen-Passaic, NJ 20 22 6 0 0 0 0 1 2 1 1 1 2 1 4 2 1
Birmingham, AL 57 44 21 11 50 25 29 38 65 68 41 28 17 17 35 33 41
Boston, MA-NH 80 20 12 0 0 0 0 0 4 0 3 9 8 1 4 1 3
Buffalo-Niagara Falls, NY 41 19 10 13 12 6 5 26 22 7 24 29 13 8 23 7 18
Charleston-North Charleston, SC 21 5 10 3 1 5 5 12 13 9 0 4 3 3 8 7 5
Charlotte-Gastonia-Rock Hill, NC-SC 69 56 9 15 32 40 41 67 62 40 32 42 12 17 26 21 33
Chicago, IL 148 24 40 11 29 14 15 20 27 17 38 34 19 13 29 9 23
Cincinnati, OH-KY-IN 93 47 18 29 33 30 20 36 40 22 28 42 22 8 33 15 39
Cleveland-Lorain-Elyria, OH 83 23 27 32 30 29 23 40 50 29 44 39 22 22 36 17 22
Columbus, OH 30 30 7 23 27 26 17 40 37 16 20 38 12 3 20 5 13
Dallas, TX 91 15 7 35 36 22 35 54 33 44 32 18 13 15 33 28 11
Dayton-Springfield, OH 24 16 7 28 28 28 22 38 28 14 15 45 13 8 22 5 11
Denver, CO 83 23 22 13 11 12 7 18 9 15 17 26 32 2 11 27 21
Detroit, MI 76 21 32 21 20 26 18 33 41 17 41 34 25 11 38 12 21
El Paso, TX 60 18 12 8 6 10 5 12 7 15 13 10 10 3 8 8 6
Fort Lauderdale, FL 36 7 12 3 3 2 3 9 7 5 5 3 0 1 1 4 7
Fort Worth-Arlington, TX 37 21 6 53 52 28 27 32 33 38 31 37 38 25 43 34 12
Fresno, CA 44 105 20 90 91 105 118 86 164 164 186 204 167 84 95 97 93
Gary, IN 63 16 16 12 30 17 15 22 33 18 45 27 15 8 19 3 11
Grand Rapids-Muskegon-Holland, MI 41 23 13 30 32 19 19 32 36 15 31 31 22 9 31 16 22
Greensboro-Winston Salem-High Point, NC 62 39 9 20 25 18 30 48 38 29 22 42 13 5 14 8 21
Greenville-Spartanburg-Anderson, SC 25 14 9 14 30 27 40 57 56 47 31 49 13 13 22 20 14
Harrisburg-Lebanon-Carlisle, PA 16 19 8 28 28 17 21 37 31 17 42 35 13 8 19 13 19
Hartford, CT 31 16 6 23 26 10 18 22 22 14 26 30 13 9 19 12 16
Honolulu, HI 30 0 11 0 0 0 0 0 2 2 2 2 2 2 2 1 0
Houston, TX 103 38 23 55 82 38 58 61 64 57 42 40 47 37 49 31 25
Indianapolis, IN 88 35 27 45 39 32 27 36 43 17 27 38 17 4 34 14 24
Jacksonville, FL 27 9 14 1 1 2 1 14 6 3 5 1 0 4 6 7 8
Jersey City, NJ 17 14 8 19 21 15 20 16 28 9 17 22 10 5 13 13 12
Kansas City, MO-KS 79 20 15 23 34 15 23 25 14 23 14 23 22 1 26 24 10
Knoxville, TN 54 57 19 38 60 58 70 97 98 65 58 69 31 14 39 30 51
Las Vegas, NV-AZ 98 25 8 22 6 21 9 9 8 6 2 13 10 4 9 12 7
Little Rock-North Little Rock, AR 28 11 6 8 24 9 10 13 16 29 17 18 3 0 19 11 11
Los Angeles-Long Beach, CA 124 100 44 145 124 97 65 64 71 83 105 94 106 99 60 56 59
Louisville, KY-IN 55 37 17 47 41 28 32 48 78 29 36 50 21 9 39 15 30
Memphis, TN-AR-MS 44 38 14 37 56 39 35 55 56 52 33 34 29 11 37 30 35
Miami, FL 20 3 11 4 8 3 4 6 9 8 2 2 2 3 0 6 3
Middlesex-Somerset-Hunterdon, NJ 15 30 4 19 31 19 28 39 35 19 29 36 11 15 22 9 21
Milwaukee-Waukesha, WI 55 14 16 17 23 15 6 16 26 9 25 22 17 6 24 6 11
Minneapolis-St. Paul, MN-WI 130 10 20 4 9 0 4 4 4 8 10 4 5 0 7 1 5
Monmouth-Ocean, NJ 5 21 4 41 34 31 32 46 35 19 35 46 25 22 27 19 21
Nashville, TN 51 38 19 31 46 46 44 45 66 49 23 33 20 7 26 17 35
Nassau-Suffolk, NY 22 16 5 28 20 14 23 27 28 12 14 22 15 6 19 11 14
New Haven-Meriden, CT 37 7 2 0 0 0 0 0 0 2 2 1 3 1 3 1 0
New Orleans, LA 61 17 13 23 37 15 22 19 42 33 19 7 16 12 16 14 17
New York, NY 131 27 18 26 25 21 33 27 27 26 33 37 17 13 23 17 20
Newark, NJ 44 21 16 33 33 24 23 35 36 17 34 43 14 8 18 25 21
Norfolk-Virginia Beach-Newport News, VA_NC 29 9 7 19 22 12 37 34 32 23 14 31 10 5 12 11 9
Oakland, CA 86 7 19 5 13 9 2 11 20 12 15 23 13 8 6 13 5
Oklahoma City, OK 30 5 9 21 29 10 15 35 17 16 24 10 13 6 12 31 4
Omaha, NE-IA 39 5 13 1 4 0 1 7 7 3 2 0 1 1 1 0 1
Orange County, CA 30 19 8 30 20 13 8 7 7 11 6 6 15 10 0 7 9
Orlando, FL 24 11 13 7 9 6 6 23 13 14 12 5 4 5 8 8 8
Philadelphia, PA-NJ 98 40 42 48 54 41 41 61 51 37 51 59 34 20 35 30 40
Phoenix-Mesa, AZ 160 205 26 33 41 45 33 47 47 35 25 22 26 9 23 25 11
Pittsburgh, PA 116 58 39 35 36 30 32 47 50 40 56 59 42 40 54 41 44
Portland-Vancouver, OR-WA 63 10 12 5 4 12 0 9 6 5 4 7 2 4 4 2 5
Providence-Fall River-Warwick, RI-MA 54 19 8 20 17 10 16 10 14 13 21 24 8 4 13 6 11
Raleigh-Durham-Chapel Hill, NC 60 29 6 11 10 13 29 46 43 16 11 39 8 3 12 7 17
Richmond-Petersburg, VA 31 25 9 26 28 23 40 50 39 17 24 40 14 5 23 14 19
Riverside-San Bernardino, CA 146 177 44 167 154 147 131 117 151 171 183 175 158 147 141 128 135
Rochester, NY 17 10 1 8 10 1 10 11 17 2 14 16 5 0 0 2 7
Sacramento, CA 92 57 21 69 61 70 39 55 93 65 72 90 66 55 58 74 32
St, Louis, MO-IL 143 41 35 49 46 35 32 45 45 30 36 49 29 11 47 22 34
Salt Lake City-Ogden, UT 74 47 13 27 8 14 3 20 18 23 29 34 20 38 32 21 28
San Antonio, TX 29 4 2 7 32 7 10 12 20 5 4 26 18 6 10 8 3
San Diego, CA 62 35 26 90 94 61 39 51 49 58 53 35 40 27 26 39 33
San Francisco, CA 30 4 12 0 3 1 0 0 11 4 12 17 3 2 2 1 2
San Jose, CA 33 7 4 5 16 18 2 14 5 0 4 8 9 3 3 11 0
SanJuan-Bayamon, PR 53 1 10 0 0 1 1 0 0 0 1 0 0 0 0 0 1
Scranton-Wilkes Barre-Hazleton, PA 19 7 12 19 25 14 19 26 25 8 24 30 7 4 12 3 7
Seattle-Bellevue-Everett, WA 89 10 10 2 0 2 0 3 6 8 6 7 2 2 2 5 4
Springfield, MA 42 22 10 28 17 8 22 24 18 7 28 24 13 9 16 12 21
Syracuse, NY 19 10 5 8 10 3 6 10 12 2 13 19 4 0 8 3 8
Tacoma, WA 25 14 4 3 3 4 0 6 2 15 11 9 8 4 4 9 7
Tampa-St. Petersburg-Clearwater, FL 73 14 24 10 14 8 24 20 23 29 18 5 13 11 15 9 12
Toledo, OH 18 8 6 12 15 20 8 15 18 9 24 23 15 9 25 4 5
Tucson, AZ 51 1 20 10 14 8 8 7 8 5 0 7 7 0 8 9 1
Tulsa, OK 29 5 8 26 39 23 12 24 24 21 21 22 16 1 19 24 2
Ventura, CA 38 23 14 97 100 95 75 54 54 57 52 26 47 41 36 31 22
Washington, DC-MD-VA-WV 124 44 39 43 54 39 51 65 61 35 41 54 21 21 36 32 38
West Palm Beach-Boca Raton, FL 24 3 4 0 0 0 0 0 0 1 0 0 0 0 0 0 2
Wilmington-Newark, DE-MD 41 27 9 46 47 22 31 42 40 24 36 34 24 10 22 20 25
Youngstown-Warren, OH 29 20 8 7 14 15 14 34 24 11 25 28 11 4 17 2 14

KEY: AQI = Air Quality Index; R = revised.

NOTES

The Air Quality Index (AQI) integrates information on 6 major pollutants (particulate matter less than 10 microns in diameter, particulate matter less than 2.5 microns in diameter, sulfur dioxide, carbon monoxide, ozone, and nitrogen dioxide) across an entire monitoring network into a single number that represents the worst daily air quality experienced in an urban area. An AQI greater than 100 indicates that at least 1 criteria pollutant exceeded air quality standards on a given day; therefore, air quality would be in the unhealthful range on that day. Air quality monitoring sites are selected as "trend sites" if they have complete data for at least 8 of the 10 last years.

The major reason for revisions to the historical data for the AQI is that changes in the National Ambient Air Quality Standards (NAAQS) are retroactively applied to the data for previous years to provide consistent comparisons over time. In addition, data from monitoring stations that have fallen below/surpassed the criterion to qualify as a 'trend site' is excluded/included in the latest calculation of the index.

Data for 1999 to 2007 include particulate matter 2.5 micron in diameter (PM 2.5).

Particulate matter is the term for solid or liquid particles found in the air.

SOURCE

U.S. Environmental Protection Agency, Office of Air and Radiation, Air Trends, Air Quality Index Information, available at http://www.epa.gov/air/airtrends/aqi_info.html as of February 2009.
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