ARB Logo California Map with Basin Highlighted
Basin by Basin Comparison of 1997 Ozone Data
Basin Name 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*
Great Basin Valleys 0 0 0 0.09 0.09   0.080 0.077
Lake County 0 0 0 0.08 0.08 0.076 0.065 0.058
Lake Tahoe 1 0 0 0.10 0.08 0.083 0.071 0.068
Mojave Desert 101 22 78 0.19 0.18 0.171 0.133 0.124
Mountain Counties 29 2 28 0.15 0.13   0.112 0.099
North Central Coast 1 0 1 0.11 0.11 0.112 0.091 0.084
North Coast 2 0 1 0.10 0.09 0.091 0.091 0.072
Northeast Plateau 0 0 0 0.08 0.07   0.074 0.058
Sacramento Valley 25 3 15 0.14 0.13 0.141 0.107 0.097
Salton Sea 91 13 63 0.16 0.16 0.157 0.120 0.107
San Diego 43 1 16 0.14 0.14 0.132 0.112 0.099
San Francisco B. A. 8 0 0 0.11 0.14 0.149 0.084 0.090
San Joaquin Valley 110 16 95 0.15 0.16 0.167 0.127 0.115
South Central Coast 59 3 46 0.14 0.15 0.154 0.114 0.115
South Coast 144 64 118 0.21 0.22 0.229 0.148 0.148
* 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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