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State of California California Air Resources Board
January - August 26th
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 19 8 18 0.15 0.14
1999 18 4 14 0.15 0.13
2000 11 1 9 0.13 0.10
2001** 28 3 22 0.14 0.11

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

Sacramento Sloughhouse 1998 16 4 15 0.15 0.11
1999 13 4 8 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 31 8 24 0.16 0.14
1999 30 7 27 0.16 0.13
2000 37 6 30 0.14 0.11
2001** 42 3 36 0.14 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 30 7 22 0.16 0.14
1999 15 0 11 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 4 0 3 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 33 7 24 0.16 0.14
1999 18 0 12 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 13 3 5 0.15 0.11
1999 7 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 7 1 4 0.15 0.11
1999 5 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 18 4 9 0.15 0.11
1999 10 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 48 19 47 0.17 0.12
1999 29 1 29 0.14 0.12
2000 35 3 32 0.13 0.11
2001** 41 6 37 0.15 0.12

Fresno Fresno-
1st Street
1998 33 11 33 0.15 0.12
1999 26 2 29 0.14 0.12
2000 35 2 31 0.14 0.11
2001** 37 4 30 0.14 0.11

Fresno Parlier 1998 49 10 44 0.16 0.12
1999 40 6 36 0.16 0.11
2000 61 12 50 0.14 0.11
2001** 55 7 44 0.15 0.12

Kern Arvin-
Bear Mountain Blvd
1998 54 8 51 0.15 0.12
1999 53 5 46 0.13 0.11
2000 63 7 55 0.14 0.11
2001** 57 11 52 0.13 0.12

Kern Edison 1998 54 15 48 0.17 0.14
1999 38 2 33 0.14 0.11
2000 58 5 49 0.15 0.11
2001** 40 5 37 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 67 29 62 0.17 0.14
1999 70 13 70 0.16 0.12
2000 85 20 78 0.15 0.12
2001** 74 20 70 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 43 22 31 0.22 0.17
1999 20 3 4 0.14 0.10
2000 35 9 18 0.17 0.15
2001** 53 14 29 0.19 0.14

Riverside Riverside-
Rubidoux
1998 51 22 42 0.19 0.17
1999 32 3 19 0.14 0.11
2000 36 2 22 0.14 0.11
2001** 37 6 31 0.14 0.12

San Bernardino Crestline 1998 77 46 69 0.24 0.21
1999 78 27 69 0.17 0.14
2000 83 18 63 0.18 0.15
2001** 76 25 70 0.17 0.14

San Bernardino Rim High School¹ 1998 80 42 78 0.24 0.21
1999 81 25 84 0.17 0.15
2000 90 27 82 0.19 0.16
2001** 63 22 63 0.16 0.14

San Bernardino San Bernardino-
4th Street
1998 51 32 37 0.21 0.18
1999 39 11 25 0.16 0.13
2000 43 7 20 0.15 0.13
2001** 47 16 36 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 81 48 74 0.24 0.21
1999 84 34 75 0.17 0.14
2000 98 29 82 0.18 0.15
2001** 96 33 84 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
Ventura Ojai-Ojai Road 1998 11 0 9 0.11 0.10
1999 4 0 4 0.11 0.09
2000 12 0 11 0.11 0.10
2001** 13 1 10 0.13 0.11

Ventura Simi Valley-
Cochran Street
1998 29 3 25 0.17 0.15
1999 20 1 20 0.13 0.11
2000 23 0 22 0.12 0.11
2001** 26 2 13 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 30 4 26 0.17 0.15
1999 20 1 20 0.13 0.11
2000 29 0 25 0.12 0.11
2001** 28 2 18 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 August 27, 2001
 
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