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State of California California Air Resources Board
January - August 19th
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 18 8 16 0.15 0.14
1999 14 3 11 0.15 0.13
2000 9 1 7 0.13 0.10
2001** 26 3 21 0.14 0.11

Sacramento Sacramento-
Del Paso Manor
1998 10 5 5 0.16 0.13
1999 5 1 3 0.13 0.11
2000 10 0 6 0.12 0.10
2001** 11 1 8 0.14 0.11

Sacramento Sloughhouse 1998 15 4 13 0.15 0.11
1999 8 2 4 0.13 0.11
2000 17 3 13 0.14 0.11
2001** 22 0 19 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 29 8 22 0.16 0.14
1999 23 4 20 0.15 0.13
2000 34 6 28 0.14 0.11
2001** 40 3 35 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 27 6 20 0.16 0.14
1999 12 0 7 0.12 0.10
2000 16 0 9 0.12 0.11
2001** 16 1 11 0.14 0.12

San Diego Escondido-
Valley Parkway
1998 4 0 3 0.12 0.09
1999 0 0 0 0.09 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 30 6 22 0.16 0.14
1999 15 0 8 0.12 0.10
2000 20 0 12 0.12 0.11
2001** 20 1 11 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 5 2 3 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 2 2 2 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 17 4 8 0.15 0.11
1999 6 2 3 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 43 19 42 0.17 0.12
1999 24 1 24 0.14 0.12
2000 33 3 29 0.13 0.11
2001** 39 6 35 0.15 0.12

Fresno Fresno-
1st Street
1998 30 11 30 0.15 0.12
1999 21 2 24 0.14 0.12
2000 33 2 30 0.14 0.11
2001** 36 4 29 0.14 0.11

Fresno Parlier 1998 44 10 41 0.16 0.12
1999 35 4 31 0.16 0.11
2000 57 11 47 0.14 0.11
2001** 53 6 42 0.15 0.12

Kern Arvin-
Bear Mountain Blvd
1998 47 7 44 0.15 0.12
1999 46 1 40 0.13 0.11
2000 57 6 50 0.14 0.11
2001** 55 10 50 0.13 0.12

Kern Edison 1998 47 12 41 0.17 0.14
1999 33 0 28 0.12 0.10
2000 53 4 44 0.15 0.11
2001** 38 4 35 0.13 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 60 25 55 0.17 0.14
1999 63 8 63 0.16 0.12
2000 79 18 73 0.15 0.12
2001** 72 19 68 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 39 20 29 0.22 0.17
1999 17 1 2 0.14 0.09
2000 33 9 18 0.17 0.15
2001** 49 12 26 0.18 0.14

Riverside Riverside-
Rubidoux
1998 46 21 38 0.19 0.17
1999 28 2 17 0.14 0.11
2000 35 2 21 0.14 0.11
2001** 34 4 28 0.14 0.12

San Bernardino Crestline 1998 70 43 64 0.24 0.21
1999 73 26 65 0.17 0.14
2000 77 18 57 0.18 0.15
2001** 72 23 66 0.17 0.14

San Bernardino Rim High School¹ 1998 74 40 72 0.24 0.21
1999 75 25 79 0.17 0.15
2000 84 27 76 0.19 0.16
2001** 59 19 59 0.16 0.14

San Bernardino San Bernardino-
4th Street
1998 47 30 34 0.21 0.18
1999 35 9 23 0.16 0.13
2000 41 7 20 0.15 0.13
2001** 43 13 32 0.16 0.13
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 74 45 68 0.24 0.21
1999 77 32 70 0.17 0.14
2000 91 29 75 0.18 0.15
2001** 90 30 80 0.18 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 10 0 9 0.11 0.10
1999 3 0 3 0.11 0.09
2000 12 0 11 0.11 0.10
2001** 12 1 10 0.13 0.11

Ventura Simi Valley-
Cochran Street
1998 27 3 24 0.17 0.15
1999 16 0 16 0.12 0.10
2000 21 0 22 0.12 0.11
2001** 24 2 11 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 27 4 25 0.17 0.15
1999 16 0 16 0.12 0.10
2000 27 0 25 0.12 0.11
2001** 26 2 16 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 20, 2001
 
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