California Air Resources Board California Map with Basin Highlighted
Ozone Data Summaries (1980-1998)
Mountain Counties Air Basin
Year Number of Days Standard Exceeded Ozone Concentrations in ppm
1 hour 8 hour
State
1hr
Federal
1hr
Federal
8hr
Max
1hr
3 Year
4th High*
EPDC*
Max
8hr
3 Year Avg
4th High*
1998 40 5 42 0.16 0.14 0.147 0.127 0.103
1997 29 2 28 0.15 0.13   0.112 0.099
1996 65 7 59 0.14 0.13   0.113 0.103
1995 49 3 47 0.15 0.12 0.131 0.113 0.099
1994 57 2 49 0.13 0.12 0.127 0.108 0.099
1993 35 0 34 0.12 0.12   0.111 0.096
1992 54 1 47 0.13 0.12   0.112 0.098
1991 23 0 33 0.11 0.11 0.118 0.102 0.092
1990 22 2 22 0.15 0.14   0.115 0.094
1989 39 2 38 0.13 0.14   0.110 0.103
1988 39 7 35 0.16 0.14   0.138 0.108
1987 0 0 0 0.08 0.08   0.073 0.071
1986 0 0 0 0.09 0.08   0.078 0.073
1981 0 0 1 0.09 0.09   0.087 0.076
* The 3 year 4th high, 3 year average 4th high, and Expected Peak Day Concentration (EPDC) are calculated based on data for 3 successive years, listed by the last year of the three year period.  The EPDC represents the ozone concentration expected to occur once per year.
   

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This page last revised on March 26, 1999

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