ARB Logo California Map with Basin Highlighted
Basin by Basin Comparison of 1993 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
3rd High*
  Great Basin Valleys 0 0 0 0.09 0.12 0.106 0.077 0.081
  Lake County 0 0 0 0.08 0.08 0.076 0.072 0.061
  Lake Tahoe 0 0 0 0.09 0.09   0.071 0.077
  Mojave Desert 135 69 123 0.20 0.20 0.192 0.147 0.146
  Mountain Counties 35 0 34 0.12 0.12 0.102 0.111 0.100
  North Central Coast 12 0 4 0.11 0.11 0.110 0.088 0.086
  North Coast 0 0 0 0.09 0.09 0.061 0.074 0.071
  Northeast Plateau 0 0 0 0.07 0.07 0.072 0.070 0.053
  Sacramento Valley 34 7 22 0.15 0.15 0.157 0.120 0.113
  Salton Sea 113 36 80 0.21 0.17 0.159 0.129 0.122
  San Diego 85 13 56 0.18 0.15 0.150 0.154 0.117
  San Francisco B.A. 19 3 5 0.13 0.12 0.125 0.113 0.087
  San Joaquin Valley 125 43 104 0.16 0.16 0.162 0.125 0.115
  South Central Coast 63 14 53 0.14 0.15 0.157 0.130 0.119
  South Coast 185 124 161 0.28 0.30 0.285 0.195 0.181
* The 3 year 4th high, 3 year average 3rd 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.
** Proposed Federal Standard

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This page last revised on April 5, 1997

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