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State of California California Air Resources Board
January 1st - September 30th
Years 1998 - 2001 Year-to-Date Ozone Summary
for Selected California Monitoring Sites and Regions

The tables below include ozone summary statistics for 2001 through the date given above. For comparison, the 1998, 1999, and 2000 summary statistics are for the year-to-date. To view the 1998, 1999, and 2000 summary statistics for the full year, click on Full Year.

Previous Ozone Summaries

Greater Sacramento Planning Area
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
1998 31 10 26 0.15 0.14
1999 22 4 18 0.15 0.13
2000 16 1 14 0.13 0.10
2001** 32 3 24 0.14 0.11

Sacramento Sacramento-
Del Paso Manor
1998 19 5 10 0.16 0.13
1999 10 1 6 0.13 0.11
2000 12 0 8 0.12 0.10
2001** 12 1 9 0.14 0.11

Sacramento Sloughhouse 1998 27 8 24 0.15 0.12
1999 24 4 16 0.15 0.11
2000 21 3 17 0.14 0.11
2001** 23 0 20 0.12 0.10
Region* Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
Greater Sacramento Planning Area
Summary
1998 47 13 34 0.16 0.14
1999 49 7 43 0.16 0.13
2000 44 7 36 0.14 0.11
2001** 51 4 45 0.15 0.11
* For the Regional summary statistics, the number of exceedance days equals the number of distinct days on which the relevant standard was exceeded at any monitoring site in the area.  If the standard was exceeded at more than one site on a given day, it only counts as one exceedance day for the broader area.  
** All 2001 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
1998 42 8 31 0.16 0.14
1999 19 0 14 0.12 0.10
2000 18 0 11 0.12 0.11
2001** 19 1 14 0.14 0.12

San Diego Escondido-
Valley Parkway
1998 8 0 5 0.12 0.09
1999 1 0 0 0.10 0.08
2000 6 0 3 0.12 0.11
2001** 3 1 1 0.14 0.10

San Diego Otay Mesa-
Paseo International
1998 0 0 0 0.09 0.08
1999 0 0 0 0.09 0.07
2000 0 0 0 0.08 0.06
2001** 0 0 0 0.09 0.07
Region* Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
San Diego Air Basin Summary 1998 47 9 33 0.16 0.14
1999 23 0 15 0.12 0.10
2000 23 0 15 0.12 0.11
2001** 26 2 16 0.14 0.12
* For the Regional summary statistics, the number of exceedance days equals the number of distinct days on which the relevant standard was exceeded at any monitoring site in the area.  If the standard was exceeded at more than one site on a given day, it only counts as one exceedance day for the broader area.  
** All 2001 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-
Rincon¹
1998 21 6 10 0.15 0.11
1999 10 2 4 0.15 0.12
2000 6 1 2 0.15 0.11
2001** 8 0 2 0.11 0.09

Contra Costa Concord-
2975 Treat Blvd
1998 13 2 6 0.15 0.11
1999 7 2 5 0.16 0.12
2000 2 1 1 0.14 0.09
2001** 6 1 1 0.13 0.09

Santa Clara San Jose-
935 Piedmont Road
1998 5 1 0 0.13 0.08
1999 2 0 0 0.12 0.08
2000 1 0 0 0.10 0.07
2001** 0 0 0 0.09 0.06
Region* Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
San Francisco Bay Area Air Basin
Summary
1998 29 8 16 0.15 0.11
1999 15 3 7 0.16 0.12
2000 11 3 4 0.15 0.11
2001** 14 1 7 0.13 0.10
¹ The new Livermore-Rincon site, which is a replacement for the Livermore-Old 1st Street site, started operating at the begining of 2000.
* For the Regional summary statistics, the number of exceedance days equals the number of distinct days on which the relevant standard was exceeded at any monitoring site in the area.  If the standard was exceeded at more than one site on a given day, it only counts as one exceedance day for the broader area.  
** All 2001 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
1998 63 26 62 0.17 0.13
1999 48 5 45 0.14 0.12
2000 46 8 43 0.15 0.13
2001** 60 6 51 0.15 0.12

Fresno Fresno-
1st Street
1998 46 15 44 0.15 0.12
1999 44 3 42 0.14 0.12
2000 45 4 40 0.14 0.11
2001** 47 4 36 0.14 0.11

Fresno Parlier 1998 64 13 54 0.16 0.12
1999 67 14 59 0.16 0.11
2000 76 16 63 0.17 0.12
2001** 81 8 63 0.15 0.12

Kern Arvin-
Bear Mountain Blvd
1998 71 12 64 0.15 0.12
1999 79 9 70 0.13 0.11
2000 78 9 70 0.15 0.12
2001** 77 14 71 0.13 0.12

Kern Edison 1998 71 22 61 0.17 0.14
1999 61 5 53 0.14 0.11
2000 68 9 55 0.15 0.12
2001** 58 6 52 0.14 0.11
Region* Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
San Joaquin Valley Air Basin Summary 1998 88 39 81 0.17 0.14
1999 99 26 96 0.16 0.12
2000 106 29 96 0.17 0.13
2001** 104 25 95 0.15 0.12
* For the Regional summary statistics, the number of exceedance days equals the number of distinct days on which the relevant standard was exceeded at any monitoring site in the area.  If the standard was exceeded at more than one site on a given day, it only counts as one exceedance day for the broader area.  
** All 2001 data are preliminary and subject to further review.  
 
South Coast Air Quality Management District
County Site Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
Los Angeles Glendora-
Laurel
1998 60 27 36 0.22 0.17
1999 24 3 7 0.14 0.10
2000 38 11 21 0.17 0.15
2001** 60 14 32 0.19 0.14

Riverside Riverside-
Rubidoux
1998 67 31 56 0.20 0.17
1999 38 3 22 0.14 0.11
2000 41 3 25 0.14 0.11
2001** 42 7 34 0.14 0.12

San Bernardino Crestline 1998 94 56 82 0.24 0.21
1999 91 30 79 0.17 0.14
2000 84 18 64 0.18 0.15
2001** 91 27 80 0.17 0.14

San Bernardino Rim High School¹ 1998 98 52 94 0.24 0.21
1999 101 28 104 0.17 0.15
2000 101 29 89 0.19 0.16
2001** 71 24 73 0.16 0.14

San Bernardino San Bernardino-
4th Street
1998 64 38 46 0.21 0.18
1999 45 14 30 0.16 0.13
2000 47 7 22 0.15 0.13
2001** 56 18 39 0.18 0.14
Region* Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
South Coast Air Quality Management District Summary 1998 102 59 89 0.24 0.21
1999 102 38 89 0.17 0.14
2000 112 32 92 0.18 0.15
2001** 118 37 99 0.19 0.14
¹ The Rim High School site is a Children Health Study site, and not a South Coast SLAMS or NAMS site.
* For the Regional summary statistics, the number of exceedance days equals the number of distinct days on which the relevant standard was exceeded at any monitoring site in the area.  If the standard was exceeded at more than one site on a given day, it only counts as one exceedance day for the broader area.  
** All 2001 data are preliminary and subject to further review.  
 
Ventura County
County Site Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
Ventura1 Ojai-Ojai Road 1998 12 0 10 0.11 0.10
1999 5 0 5 0.11 0.10
2000 15 0 14 0.11 0.10
2001** 14 1 10 0.13 0.11

Ventura1 Simi Valley-
Cochran Street
1998 35 4 27 0.17 0.15
1999 29 1 21 0.13 0.11
2000 30 1 26 0.13 0.11
2001** 30 2 17 0.13 0.11
Region* Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
Ventura County Summary1 1998 37 5 28 0.17 0.15
1999 29 1 21 0.13 0.11
2000 37 1 29 0.13 0.11
2001** 31 2 22 0.13 0.11
* For the Regional summary statistics, the number of exceedance days equals the number of distinct days on which the relevant standard was exceeded at any monitoring site in the area.  If the standard was exceeded at more than one site on a given day, it only counts as one exceedance day for the broader area.  
** All 2001 data are preliminary and subject to further review.  
 
 
Please send questions or comments to:
aqdweb@cleanair.arb.ca.gov
 
This page last revised on October 3, 2001
 
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