ARB Logo California Map with Basin Highlighted
Basin by Basin Comparison of 1998 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 1 0.09 0.09   0.085 0.079
Lake County 0 0 0 0.08 0.08 0.077 0.076 0.057
Lake Tahoe 0 0 0 0.08 0.08 0.082 0.077 0.069
Mojave Desert 77 26 68 0.20 0.17 0.176 0.144 0.127
Mountain Counties 40 5 42 0.16 0.14 0.147 0.127 0.103
North Central Coast 10 0 6 0.12 0.11 0.114 0.097 0.086
North Coast 7 1 5 0.13 0.11 0.103 0.106 0.077
Northeast Plateau 0 0 0 0.08 0.08   0.071 0.061
Sacramento Valley 62 14 60 0.16 0.15   0.137 0.097
Salton Sea 68 11 38 0.17 0.16 0.153 0.136 0.107
San Diego 47 9 33 0.16 0.14 0.135 0.141 0.102
San Francisco B. A. 29 8 16 0.15 0.14 0.151 0.111 0.089
San Joaquin Valley 88 39 82 0.17 0.16 0.162 0.136 0.115
South Central Coast 54 6 41 0.17 0.14 0.143 0.151 0.112
South Coast 107 60 92 0.24 0.22 0.224 0.206 0.154
* 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.
   

Please send questions or comments to:

aqdweb@arb.ca.gov

This page last revised on March 26, 1999

Other Pollutants  |  Ozone Home Page  |  Air Basin (Site) Selection Map  |  Map for this Basin 
District/Site Directory  |  County/Site Directory  |  Monitoring Site Directory 
ARB Home Page  |   Search ARB Programs/Topics  |   Email ARB Help Attendant