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State of California California Air Resources Board
January 1st - September 16th
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 13 1 11 0.13 0.10
2001** 31 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 10 0 6 0.12 0.10
2001** 12 1 9 0.14 0.11

Sacramento Sloughhouse 1998 27 8 24 0.15 0.11
1999 20 4 14 0.15 0.11
2000 20 3 16 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 42 7 38 0.16 0.13
2000 40 7 33 0.14 0.11
2001** 48 4 43 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 39 8 29 0.16 0.14
1999 19 0 14 0.12 0.10
2000 18 0 11 0.12 0.11
2001** 19 1 13 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** 2 0 0 0.11 0.08

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 0.08 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 44 9 31 0.16 0.14
1999 22 0 15 0.12 0.10
2000 23 0 15 0.12 0.11
2001** 23 1 13 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 9 2 4 0.15 0.12
2000 5 1 2 0.15 0.11
2001** 7 0 2 0.11 0.09

Contra Costa Concord-
2975 Treat Blvd
1998 13 2 6 0.15 0.11
1999 6 2 4 0.16 0.12
2000 1 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 12 3 6 0.16 0.12
2000 10 3 4 0.15 0.11
2001** 13 1 6 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 42 5 41 0.14 0.12
2000 41 6 38 0.15 0.13
2001** 54 6 46 0.15 0.12

Fresno Fresno-
1st Street
1998 46 15 44 0.15 0.12
1999 39 3 41 0.14 0.12
2000 40 3 35 0.14 0.11
2001** 45 4 35 0.14 0.11

Fresno Parlier 1998 63 13 54 0.16 0.12
1999 56 13 51 0.16 0.11
2000 69 13 58 0.14 0.11
2001** 72 7 58 0.15 0.12

Kern Arvin-
Bear Mountain Blvd
1998 70 12 64 0.15 0.12
1999 70 8 61 0.13 0.11
2000 73 8 65 0.14 0.12
2001** 70 13 64 0.13 0.12

Kern Edison 1998 70 22 61 0.17 0.14
1999 52 4 45 0.14 0.11
2000 62 6 51 0.15 0.12
2001** 49 6 46 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 86 39 80 0.17 0.14
1999 87 23 86 0.16 0.12
2000 97 24 89 0.15 0.13
2001** 93 23 87 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 58 27 36 0.22 0.17
1999 23 3 7 0.14 0.10
2000 37 10 20 0.17 0.15
2001** 55 14 30 0.19 0.14

Riverside Riverside-
Rubidoux
1998 64 31 54 0.20 0.17
1999 37 3 22 0.14 0.11
2000 40 2 24 0.14 0.11
2001** 38 6 32 0.14 0.12

San Bernardino Crestline 1998 90 55 79 0.24 0.21
1999 85 30 75 0.17 0.14
2000 84 18 64 0.18 0.15
2001** 85 27 75 0.17 0.14

San Bernardino Rim High School¹ 1998 94 51 90 0.24 0.21
1999 94 28 97 0.17 0.15
2000 97 28 87 0.19 0.16
2001** 68 24 67 0.16 0.14

San Bernardino San Bernardino-
4th Street
1998 62 38 45 0.21 0.18
1999 44 14 30 0.16 0.13
2000 45 7 21 0.15 0.13
2001** 53 17 37 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 98 58 86 0.24 0.21
1999 95 38 83 0.17 0.14
2000 106 30 88 0.18 0.15
2001** 108 35 90 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 County1
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 13 0 11 0.11 0.10
2001** 13 1 10 0.13 0.11

Ventura1 Simi Valley-
Cochran Street
1998 35 4 27 0.17 0.15
1999 28 1 21 0.13 0.11
2000 26 0 23 0.12 0.11
2001** 28 2 15 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 28 1 21 0.13 0.11
2000 32 0 26 0.12 0.11
2001** 30 2 20 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.  
1 Ventura data for 2001 represents through August 29, 2001.  
 
 
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aqdweb@cleanair.arb.ca.gov
 
This page last revised on September 17, 2001
 
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