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State of California California Air Resources Board
January 1st - September 2nd
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 25 10 23 0.15 0.14
1999 19 4 15 0.15 0.13
2000 11 1 9 0.13 0.10
2001** 30 3 24 0.14 0.11

Sacramento Sacramento-
Del Paso Manor
1998 14 5 7 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 21 6 20 0.15 0.11
1999 15 4 9 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 38 11 29 0.16 0.14
1999 32 7 28 0.16 0.13
2000 37 6 30 0.14 0.11
2001** 46 4 40 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 17 0 13 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 20 0 14 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 17 5 6 0.15 0.11
1999 8 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 9 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 24 6 11 0.15 0.11
1999 11 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 55 25 54 0.17 0.13
1999 31 2 31 0.14 0.12
2000 36 3 33 0.13 0.11
2001** 47 6 42 0.15 0.12

Fresno Fresno-
1st Street
1998 40 15 39 0.15 0.12
1999 28 2 31 0.14 0.12
2000 36 2 32 0.14 0.11
2001** 41 4 33 0.14 0.11

Fresno Parlier 1998 56 12 51 0.16 0.12
1999 42 6 38 0.16 0.11
2000 63 13 52 0.14 0.11
2001** 61 7 50 0.15 0.12

Kern Arvin-
Bear Mountain Blvd
1998 60 12 56 0.15 0.12
1999 56 5 48 0.13 0.11
2000 65 7 57 0.14 0.11
2001** 64 13 58 0.13 0.12

Kern Edison 1998 60 20 54 0.17 0.14
1999 40 2 35 0.14 0.11
2000 59 5 50 0.15 0.11
2001** 45 6 41 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 74 36 69 0.17 0.14
1999 73 14 73 0.16 0.12
2000 88 21 81 0.15 0.12
2001** 81 23 76 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 49 24 33 0.22 0.17
1999 22 3 6 0.14 0.10
2000 35 9 18 0.17 0.15
2001** 54 14 30 0.19 0.14

Riverside Riverside-
Rubidoux
1998 56 27 47 0.20 0.17
1999 35 3 21 0.14 0.11
2000 36 2 22 0.14 0.11
2001** 38 6 32 0.14 0.12

San Bernardino Crestline 1998 82 51 74 0.24 0.21
1999 82 29 72 0.17 0.14
2000 84 18 64 0.18 0.15
2001** 80 27 73 0.17 0.14

San Bernardino Rim High School¹ 1998 85 46 83 0.24 0.21
1999 85 27 87 0.17 0.15
2000 91 27 83 0.19 0.16
2001** 67 24 66 0.16 0.14

San Bernardino San Bernardino-
4th Street
1998 56 36 40 0.21 0.18
1999 42 12 28 0.16 0.13
2000 43 7 20 0.15 0.13
2001** 49 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 88 53 79 0.24 0.21
1999 88 36 78 0.17 0.14
2000 99 29 83 0.18 0.15
2001** 100 35 87 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 12 0 11 0.11 0.10
2001** 13 1 10 0.13 0.11

Ventura Simi Valley-
Cochran Street
1998 32 4 27 0.17 0.15
1999 25 1 21 0.13 0.11
2000 23 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 34 5 28 0.17 0.15
1999 25 1 21 0.13 0.11
2000 29 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 Several days of Ventura data were not reported in late August and early September 2001.  
 
 
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This page last revised on September 5, 2001
 
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