Table 7-7: Air Pollution in the 50 Largest Metropolitan Areas: 2001-2008

Table 7-7: Air Pollution in the 50 Largest Metropolitan Areas: 2001-2008

(Number of days with AQI values greater than 100)

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Metropolitan area AQI days > 100
(R) 2001 (R) 2002 (R) 2003 (R) 2004 (R) 2005 (R) 2006 (R) 2007 2008
Atlanta-Sandy Springs-Marietta, GA 39 41 23 21 30 40 37 24
Austin-Round Rock, TX 5 8 9 8 9 13 4 2
Baltimore-Towson, MD 50 59 31 31 36 34 45 23
Birmingham-Hoover, AL 41 28 17 17 35 33 41 11
Boston-Cambridge-Quincy, MA-NH 3 11 8 1 4 1 3 0
Buffalo-Niagara Falls, NY 24 29 13 8 23 6 18 4
Charlotte-Gastonia-Concord, NC-SC 31 41 12 16 25 21 33 16
Chicago-Naperville-Joliet, IL-IN-WI 66 39 28 20 36 11 27 2
Cincinnati-Middletown, OH-KY-IN 34 44 26 12 38 18 42 14
Cleveland-Elyria-Mentor, OH 33 34 19 20 33 16 10 12
Columbus, OH 20 38 12 3 20 5 13 4
Dallas-Fort Worth-Arlington, TX 43 40 40 32 56 39 16 20
Denver-Aurora, CO 17 26 32 2 11 27 21 10
Detroit-Warren-Livonia, MI 41 33 25 11 37 12 21 7
Hartford-West Hartford-East Hartford, CT 27 34 13 11 19 15 24 10
Houston-Sugar Land-Baytown, TX 42 40 47 37 49 31 25 17
Indianapolis-Carmel, IN 27 38 17 4 34 14 24 3
Jacksonville, FL 5 1 0 4 6 7 8 0
Kansas City, MO-KS 9 22 20 1 18 24 10 0
Las Vegas-Paradise, NV 2 13 10 4 9 12 7 0
Los Angeles-Long Beach-Santa Ana, CA 105 95 107 99 60 56 59 53
Louisville/Jefferson County, KY-IN 36 50 21 9 39 15 30 8
Memphis, TN-MS-AR 33 34 29 11 37 30 35 10
Miami-Fort Lauderdale-Pompano Beach, FL 5 3 2 3 1 6 9 5
Milwaukee-Waukesha-West Allis, WI 25 21 17 6 21 6 11 3
Minneapolis-St. Paul-Bloomington, MN-WI 10 4 5 0 7 1 5 1
Nashville-Davidson-Murfreesboro-Franklin, TN 23 33 20 7 26 17 33 9
New Orleans-Metairie-Kenner, LA 18 4 15 12 13 13 17 2
New York-Northern New Jersey-Long Island, NY-NJ-PA 54 61 33 32 41 38 38 29
Oklahoma City, OK 24 10 13 6 12 31 4 4
Orlando-Kissimmee, FL 12 5 4 5 8 8 8 1
Philadelphia-Camden-Wilmington, PA-NJ-DE-MD 57 60 37 23 36 30 42 28
Phoenix-Mesa-Scottsdale, AZ 25 22 26 9 23 25 11 11
Pittsburgh, PA 56 62 42 40 54 41 44 22
Portland-Vancouver-Beaverton, OR-WA 4 7 2 4 4 2 5 3
Providence-New Bedford-Fall River, RI-MA 27 33 17 9 19 12 12 4
Richmond, VA 24 40 14 5 23 14 19 15
Riverside-San Bernardino-Ontario, CA 183 175 158 147 141 128 135 119
Rochester, NY 14 16 5 0 0 1 5 2
Sacramento--Arden-Arcade--Roseville, CA 72 90 66 55 58 74 32 44
Salt Lake City, UT 29 34 20 38 32 20 28 15
San Antonio, TX 4 26 18 6 10 8 3 7
San Diego-Carlsbad-San Marcos, CA 53 35 40 27 26 39 33 35
San Francisco-Oakland-Fremont, CA 20 28 14 10 6 13 5 7
San Jose-Sunnyvale-Santa Clara, CA 9 24 14 7 4 13 3 13
Seattle-Tacoma-Bellevue, WA 14 13 10 4 6 10 9 7
St. Louis, MO-IL 35 48 29 12 45 22 34 6
Tampa-St. Petersburg-Clearwater, FL 18 5 13 11 15 9 12 7
Virginia Beach-Norfolk-Newport News, VA-NC 14 31 10 5 12 11 9 15
Washington-Arlington-Alexandria, DC-VA-MD-WV 41 54 21 21 36 31 38 16

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.

Metropolitan area rank is based on U.S. Census Bureau's population estimates for July 1, 2000 and geographic definitions for 2000 available at http://www.census.gov/popest/metro/CBSA-est2009-annual.html as of May 18, 2010. The U.S. Environmental Protection Agency reports data for metropolitan areas as they were defined in 2000.

SOURCES: U.S. Environmental Protection Agency, Office of Air and Radiation, Air Trends, Air Quality Index Information, available at http://www.epa.gov/oaqps001/airtrends/aqi_info.html as of Apr. 16, 2010.