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Air Quality Trends
(Violations / Monitor / Year)
| Year | CO | OZ |
|---|---|---|
| 1975 | 25.1 | 12.6 |
| 1976 | 23.2 | 10.7 |
| 1977 | 12.4 | 8.9 |
| 1978 | 10.6 | 11.3 |
| 1979 | 8.2 | 7.4 |
| 1980 | 6.0 | 8.8 |
| 1981 | 4.7 | 6.1 |
| 1982 | 3.8 | 4.1 |
| 1983 | 3.3 | 8.6 |
| 1984 | 3.4 | 5.6 |
| 1985 | 2.2 | 5.2 |
| 1986 | 2.1 | 4.4 |
| 1987 | 1.4 | 5.5 |
| 1988 | 1.8 | 8.0 |
| 1989 | 1.8 | 3.9 |
| 1990 | 1.2 | 3.2 |
| 1991 | 0.8 | 3.2 |
| 1992 | 0.5 | 2.5 |
| 1993 | 0.3 | 2.1 |
| 1994 | 0.4 | 2.2 |
| 1995 | 0.3 | 2.1 |
| 1996 | 0.3 | 1.1 |
| 1997 | 0.2 | 0.9 |
| 1998 | 0.2 | 1.2 |
| 1999 | 0.1 | 0.8 |
| 2000 | 0.1 | 0.5 |
Source: 1975-1995 data were tabulated from individual monitor records in EPA Aerometric Information Retreival Service (AIRS) database. These are for the subset of monitors having complete data for at least 15 of the 21 years included in that period. Supplemental 1994-2000 data were tabulated from EPA AIRSDATA Monitor Trends Report which can be found on the internet at: http://www.epa.gov/airsdata/montrnd.htm.
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