California Home Page Air Resources Board Home Page Air Quality Data Home Page Search the ARB Web Site ARB Web Site Map Software Contact the Air Resources Board Data Descriptions Page
State of California California Air Resources Board
January 1st - September 9th
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 28 10 24 0.15 0.14
1999 22 4 18 0.15 0.13
2000 11 1 9 0.13 0.10
2001** 31 3 24 0.14 0.11

Sacramento Sacramento-
Del Paso Manor
1998 17 5 9 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 24 7 22 0.15 0.11
1999 20 4 14 0.15 0.11
2000 17 3 13 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 43 12 32 0.16 0.14
1999 38 7 33 0.16 0.13
2000 37 6 30 0.14 0.11
2001** 48 4 42 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 35 8 27 0.16 0.14
1999 19 0 14 0.12 0.10
2000 16 0 9 0.12 0.11
2001** 18 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 4 0 2 0.12 0.09
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 40 9 29 0.16 0.14
1999 22 0 15 0.12 0.10
2000 20 0 12 0.12 0.11
2001** 22 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 20 5 9 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 12 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 3 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 27 7 14 0.15 0.11
1999 12 3 6 0.16 0.12
2000 9 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 57 26 56 0.17 0.13
1999 37 4 37 0.14 0.12
2000 38 4 35 0.13 0.11
2001** 51 6 44 0.15 0.12

Fresno Fresno-
1st Street
1998 41 15 40 0.15 0.12
1999 34 3 37 0.14 0.12
2000 38 2 32 0.14 0.11
2001** 43 4 34 0.14 0.11

Fresno Parlier 1998 59 12 51 0.16 0.12
1999 49 11 44 0.16 0.11
2000 66 13 55 0.14 0.11
2001** 67 7 54 0.15 0.12

Kern Arvin-
Bear Mountain Blvd
1998 64 12 58 0.15 0.12
1999 63 7 54 0.13 0.11
2000 68 8 60 0.14 0.12
2001** 67 13 61 0.13 0.12

Kern Edison 1998 64 20 55 0.17 0.14
1999 46 3 40 0.14 0.11
2000 59 5 50 0.15 0.11
2001** 47 6 44 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 80 37 74 0.17 0.14
1999 80 19 79 0.16 0.12
2000 91 22 84 0.15 0.12
2001** 87 23 81 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 53 24 33 0.22 0.17
1999 23 3 7 0.14 0.10
2000 35 9 18 0.17 0.15
2001** 54 14 30 0.19 0.14

Riverside Riverside-
Rubidoux
1998 59 28 50 0.20 0.17
1999 37 3 22 0.14 0.11
2000 36 2 22 0.14 0.11
2001** 38 6 32 0.14 0.12

San Bernardino Crestline 1998 84 52 76 0.24 0.21
1999 85 30 75 0.17 0.14
2000 84 18 64 0.18 0.15
2001** 83 27 75 0.17 0.14

San Bernardino Rim High School¹ 1998 88 48 85 0.24 0.21
1999 91 28 93 0.17 0.15
2000 93 27 84 0.19 0.16
2001** 68 24 67 0.16 0.14

San Bernardino San Bernardino-
4th Street
1998 58 36 41 0.21 0.18
1999 44 14 30 0.16 0.13
2000 43 7 20 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 92 54 82 0.24 0.21
1999 93 38 82 0.17 0.14
2000 101 29 83 0.18 0.15
2001** 104 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
Ventura 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

Ventura Simi Valley-
Cochran Street
1998 33 4 27 0.17 0.15
1999 26 1 21 0.13 0.11
2000 24 0 22 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 Summary 1998 35 5 28 0.17 0.15
1999 26 1 21 0.13 0.11
2000 30 0 25 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 have not been available since late August, 2001.  
 
 
Please send questions or comments to:
aqdweb@cleanair.arb.ca.gov
 
This page last revised on September 12, 2001
 
----------