California Air Resources Board
January - September
Year-to-Date Ozone Summary
for Selected California Monitoring Sites
   

Sacramento Valley Air Basin
County Site Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
Sacramento Folsom-
50 Natoma Street*
1996 35 7 23 0.157 0.126
1997 19 1 8 0.125 0.101
1998 31 10 26 0.151 0.137
1999** 22 4 18 0.15   0.130

Sacramento Sacramento-
Del Paso Manor
1996 26 3 13 0.150 0.110
1997 6 0 1 0.108 0.094
1998 19 5 10 0.160 0.130
1999** 10 1 6 0.13   0.111
* The 50 Natoma Street site replaced the Folsom-City Corporation Yard site in 1997.
** All 1999 data are preliminary and subject to further review.  
 
San Diego Air Basin
County Site Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
San Diego Alpine-
Victoria Drive
1996 44 2 27 0.138 0.117
1997 27 1 11 0.136 0.112
1998 42 8 31 0.164 0.141
1999** 19 0 18 0.12   0.105

San Diego Escondido-
Valley Parkway
1996 12 0 9 0.119 0.099
1997 4 0 2 0.112 0.090
1998 8 0 5 0.122 0.092
1999** 1 0 1 0.10   0.094

San Diego Otay Mesa-
Paseo International
1996 6 0 1 0.111 0.089
1997 6 0 0 0.122 0.081
1998 0 0 0 0.094 0.078
1999** 0 0 0 0.09   0.072
** All 1999 data are preliminary and subject to further review.  
 
San Francisco Bay Area Air Basin
County Site Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
Alameda Livermore-
Old 1st Street
1996 22 8 10 0.138 0.112
1997 3 0 0 0.114 0.084
1998 21 6 10 0.146 0.110
1999** 10 2 4 0.146 0.116

Contra Costa Concord-
2975 Treat Blvd
1996 11 1 4 0.127 0.099
1997 2 0 0 0.099 0.081
1998 13 2 6 0.147 0.109
1999** 7 2 5 0.156 0.122

Santa Clara San Jose-
935 Piedmont Road
1996 5 0 0 0.118 0.083
1997 1 0 0 0.095 0.071
1998 5 1 0 0.129 0.082
1999** 2 0 0 0.116 0.082
** All 1999 data are preliminary and subject to further review.  
 
San Joaquin Valley Air Basin
County Site Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
Fresno Clovis-
N Villa Avenue
1996 65 16 56 0.146 0.122
1997 68 9 63 0.147 0.127
1998 63 26 62 0.169 0.130
1999** 53 6 49 0.144 0.123

Fresno Fresno-
1st Street
1996 54 15 46 0.146 0.123
1997 30 1 23 0.128 0.107
1998 46 15 44 0.151 0.118
1999** 43 3 42 0.13   0.121

Fresno Parlier 1996 75 16 54 0.151 0.112
1997 63 9 46 0.137 0.112
1998 64 13 54 0.164 0.120
1999** 65 13 58 0.155 0.109

Kern Arvin-
Bear Mountain Blvd
1996 104 33 99 0.164 0.137
1997 55 7 45 0.134 0.112
1998 71 12 64 0.151 0.123
1999** 78 8 70 0.13   0.112

Kern Edison 1996 83 22 72 0.165 0.131
1997 48 3 29 0.146 0.118
1998 71 22 61 0.165 0.136
1999** 60 5 53 0.14   0.111
** All 1999 data are preliminary and subject to further review.  
 
South Coast Air Basin
County Site Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
Los Angeles Glendora-
Laurel
1996 84 46 50 0.205 0.150
1997 63 18 24 0.170 0.130
1998 60 27 36 0.222 0.171
1999** 17 3 7 0.142 0.105

Riverside Riverside-
Rubidoux
1996 85 34 70 0.203 0.162
1997 85 13 52 0.187 0.129
1998 67 31 56 0.195 0.169
1999** 39 3 25 0.142 0.112

San Bernardino Lake Gregory 1996 112 62 95 0.234 0.164
1997 89 29 64 0.205 0.138
1998 94 56 82 0.244 0.206
1999** 98 35 94 0.174 0.137

San Bernardino San Bernardino-
4th Street
1996 107 62 85 0.239 0.173
1997 99 32 61 0.197 0.137
1998 64 38 46 0.214 0.180
1999** 48 11 30 0.159 0.128
** All 1999 data are preliminary and subject to further review.  
 
 
Please send questions or comments to:
aqdweb@arb.ca.gov
 
This page last revised on October 7, 1999
 
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