California Air Resources Board
January - October
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** 12 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 45 2 27 0.138 0.117
1997 29 1 11 0.136 0.112
1998 46 8 32 0.164 0.141
1999** 22 0 15 0.12   0.105

San Diego Escondido-
Valley Parkway
1996 12 0 9 0.119 0.099
1997 5 0 2 0.114 0.090
1998 9 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 7 0 0 0.122 0.082
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** 14 2 5 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** 8 2 6 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 70 16 61 0.146 0.122
1997 76 9 68 0.147 0.127
1998 65 26 62 0.169 0.130
1999** 61 6 52 0.144 0.123

Fresno Fresno-
1st Street
1996 59 15 49 0.146 0.123
1997 30 1 23 0.128 0.107
1998 46 15 44 0.151 0.118
1999** 51 4 45 0.13   0.121

Fresno Parlier 1996 82 18 59 0.151 0.112
1997 68 9 48 0.137 0.112
1998 64 13 54 0.164 0.120
1999** 78 14 64 0.155 0.109

Kern Arvin-
Bear Mountain Blvd
1996 112 37 106 0.164 0.137
1997 57 7 46 0.134 0.112
1998 71 12 64 0.151 0.123
1999** 92 8 85 0.13   0.112

Kern Edison 1996 90 25 78 0.165 0.131
1997 50 3 30 0.146 0.118
1998 71 22 61 0.165 0.136
1999** 66 5 54 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 91 49 52 0.205 0.150
1997 67 18 24 0.170 0.130
1998 61 28 37 0.222 0.171
1999** 18 3 7 0.142 0.105

Riverside Riverside-
Rubidoux
1996 92 36 72 0.203 0.162
1997 89 13 52 0.187 0.129
1998 70 32 57 0.195 0.169
1999** 39 3 25 0.142 0.112

San Bernardino Lake Gregory 1996 115 62 96 0.234 0.164
1997 92 29 66 0.205 0.138
1998 97 57 85 0.244 0.206
1999** 103 35 97 0.174 0.137

San Bernardino San Bernardino-
4th Street
1996 113 63 87 0.239 0.173
1997 102 32 63 0.197 0.137
1998 65 39 47 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 November 4, 1999
 
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