California Air Resources Board California Map with County Boundaries
Ozone Data Summaries (1980-1998)
Sonoma County Portion
of the North Coast 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 7 1 5 0.13 0.11 0.103 0.106 0.077
1997 2 0 1 0.10 0.09 0.091 0.091 0.072
1996 0 0 0 0.08 0.09 0.088 0.071 0.069
1995 1 0 1 0.10 0.09 0.090 0.090 0.069
1994 1 0 0 0.10 0.09 0.089 0.080 0.066
1993 0 0 0 0.09 0.09   0.073 0.065
1992 0 0 0 0.09 0.08   0.072 0.063
* 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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