California Air Resources Board
January - August
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 34 7 23 0.157 0.126
1997 17 1 8 0.125 0.101
1998 23 9 21 0.151 0.137
1999** 19 4 15 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 12 5 7 0.160 0.130
1999** 8 1 5 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 42 2 27 0.138 0.117
1997 26 1 11 0.136 0.112
1998 33 8 25 0.164 0.141
1999** 17 0 17 0.12   0.105

San Diego Escondido-
Valley Parkway
1996 11 0 9 0.119 0.099
1997 3 0 2 0.112 0.090
1998 7 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 4 0 0 0.122 0.079
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 21 8 9 0.138 0.112
1997 3 0 0 0.114 0.084
1998 16 4 5 0.146 0.110
1999** 8 2 4 0.146 0.116

Contra Costa Concord-
2975 Treat Blvd
1996 9 1 4 0.127 0.099
1997 2 0 0 0.099 0.075
1998 8 1 4 0.147 0.109
1999** 5 2 4 0.156 0.122

Santa Clara San Jose-
935 Piedmont Road
1996 5 0 0 0.118 0.083
1997 0 0 0 0.080 0.063
1998 3 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 55 16 50 0.146 0.122
1997 49 7 47 0.147 0.127
1998 53 23 52 0.167 0.124
1999** 36 3 35 0.144 0.123

Fresno Fresno-
1st Street
1996 47 14 41 0.146 0.123
1997 26 1 22 0.128 0.107
1998 38 13 37 0.151 0.118
1999** 27 2 31 0.13   0.121

Fresno Parlier 1996 61 16 45 0.151 0.112
1997 50 9 39 0.137 0.112
1998 54 11 49 0.164 0.120
1999** 40 5 37 0.155 0.109

Kern Arvin-
Bear Mountain Blvd
1996 84 30 79 0.164 0.137
1997 47 6 40 0.130 0.112
1998 59 12 56 0.151 0.123
1999** 55 4 47 0.13   0.110

Kern Edison 1996 66 21 57 0.165 0.131
1997 38 3 25 0.146 0.118
1998 59 20 53 0.165 0.136
1999** 40 2 35 0.14   0.106
** 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 78 43 49 0.205 0.150
1997 52 14 21 0.170 0.130
1998 48 24 33 0.222 0.171
1999** 14 3 6 0.142 0.103

Riverside Riverside-
Rubidoux
1996 79 34 68 0.203 0.162
1997 72 10 47 0.187 0.129
1998 56 27 47 0.195 0.169
1999** 27 3 21 0.142 0.110

San Bernardino Lake Gregory 1996 103 62 92 0.234 0.164
1997 82 27 63 0.205 0.138
1998 82 51 74 0.244 0.206
1999** 78 30 83 0.174 0.142

San Bernardino San Bernardino-
4th Street
1996 95 59 80 0.239 0.173
1997 89 29 57 0.197 0.137
1998 56 36 40 0.214 0.180
1999** 36 7 29 0.159 0.132
** 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 September 9, 1999
 
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