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State of California California Air Resources Board
January - August 12th
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 16 6 14 0.15 0.14
1999 13 3 10 0.15 0.13
2000 6 1 5 0.13 0.10
2001** 22 3 17 0.14 0.11

Sacramento Sacramento-
Del Paso Manor
1998 9 4 4 0.16 0.13
1999 5 1 3 0.13 0.11
2000 9 0 6 0.12 0.10
2001** 11 1 8 0.14 0.11

Sacramento Sloughhouse 1998 14 4 12 0.15 0.11
1999 8 2 4 0.13 0.11
2000 15 3 12 0.14 0.11
2001** 20 0 18 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 27 6 20 0.16 0.14
1999 21 4 18 0.15 0.13
2000 29 6 24 0.14 0.11
2001** 35 3 31 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 25 6 18 0.16 0.14
1999 12 0 7 0.12 0.10
2000 14 0 9 0.12 0.11
2001** 16 1 10 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 28 6 20 0.16 0.14
1999 15 0 8 0.12 0.10
2000 18 0 12 0.12 0.11
2001** 20 1 10 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 4 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 16 4 8 0.15 0.11
1999 6 2 3 0.16 0.12
2000 8 3 4 0.15 0.11
2001** 12 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 40 18 39 0.16 0.12
1999 22 1 22 0.14 0.12
2000 30 2 27 0.13 0.11
2001** 33 4 29 0.15 0.11

Fresno Fresno-
1st Street
1998 27 10 27 0.15 0.12
1999 20 2 24 0.14 0.12
2000 30 2 28 0.14 0.11
2001** 31 3 25 0.13 0.11

Fresno Parlier 1998 41 9 38 0.16 0.12
1999 31 4 28 0.16 0.11
2000 52 9 44 0.14 0.11
2001** 47 4 36 0.13 0.11

Kern Arvin-
Bear Mountain Blvd
1998 44 6 42 0.15 0.12
1999 42 1 35 0.13 0.11
2000 51 4 44 0.14 0.11
2001** 48 7 43 0.13 0.11

Kern Edison 1998 43 12 40 0.17 0.14
1999 29 0 24 0.12 0.10
2000 47 4 40 0.15 0.11
2001** 31 2 28 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 56 23 52 0.17 0.14
1999 58 8 58 0.16 0.12
2000 72 15 66 0.15 0.12
2001** 65 15 61 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 36 20 29 0.22 0.17
1999 15 1 1 0.14 0.09
2000 29 8 16 0.17 0.15
2001** 42 11 24 0.18 0.14

Riverside Riverside-
Rubidoux
1998 42 21 34 0.19 0.17
1999 25 2 16 0.14 0.11
2000 31 1 18 0.14 0.11
2001** 30 3 26 0.14 0.12

San Bernardino Crestline 1998 63 39 57 0.24 0.21
1999 69 24 61 0.17 0.14
2000 71 16 52 0.18 0.15
2001** 65 21 59 0.17 0.14

San Bernardino Rim High School¹ 1998 67 36 65 0.24 0.21
1999 71 22 74 0.17 0.15
2000 78 24 71 0.19 0.16
2001** 53 17 53 0.16 0.14

San Bernardino San Bernardino-
4th Street
1998 42 29 30 0.21 0.18
1999 32 9 20 0.16 0.13
2000 36 6 17 0.15 0.13
2001** 37 12 30 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 67 41 61 0.24 0.21
1999 73 30 66 0.17 0.14
2000 84 27 70 0.18 0.15
2001** 83 25 73 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 8 0 7 0.11 0.09
1999 3 0 3 0.11 0.09
2000 8 0 7 0.11 0.09
2001** 9 0 8 0.11 0.10

Ventura Simi Valley-
Cochran Street
1998 25 3 22 0.17 0.15
1999 14 0 14 0.12 0.10
2000 17 0 18 0.12 0.11
2001** 19 1 10 0.13 0.10
Region* Year Exceedance Days Maximum
State Federal Concentrations (ppm)
1-hr 1-hr 8-hr 1-hr 8-hr
Ventura County Summary 1998 25 4 23 0.17 0.15
1999 14 0 14 0.12 0.10
2000 23 0 21 0.12 0.11
2001** 20 1 14 0.13 0.10
* 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 13, 2001
 
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