Highest Ozone in the Country

The Environmental Protection Agency today adopted new standards on ozone levels in the country's air.

The new "safe" level is 0.075 parts per million, down from 0.084 ppm before.

Due to the new standard level, the EPA issued a list of counties that are now above the safe level. Here are the top ten counties in entire USA with the highest levels of ozone...

  1. San Bernardino County, CA (0.121)

  2. Riverside County, CA (0.112)

  3. Los Angeles County, CA (0.112)

  4. Kern County, CA (0.110)

  5. Tulare County, CA (0.103)

  6. Harris County, TX (0.103)

  7. Fresno County, CA (0.098)

  8. Sacramento County, CA (0.097)

  9. Placer County, CA (0.097)

  10. Nevada County, CA (0.096)
9 of the top 10 are in California.

High levels of ozone are believed to cause asthma and other respiratory illnesses in children and seniors.

If you have an air purifier in your house, you might want to check it out for ozone. Many of them output ozone to kill microscopic organisms in the air.

If you're thinking about moving, here's a list of the top 10 counties with the lowest levels of ozone...

  1. Honolulu, HI (0.042)

  2. San Francisco County, CA (0.045)

  3. Marin County, CA (0.050)

  4. Yukon-Koyukuk, AK (0.052)

  5. San Mateo County, CA (0.053)

  6. Dunn County, ND (0.055)

  7. Flathead County, MT (0.056)

  8. Lancaster County, NE (0.056)

  9. Burke County, ND (0.057)

  10. Oliver County, ND (0.057)
In case you're wondering, both Orange County and San Diego County exceed the safe standard.

You can download the full list of counties that are above and below the standard...



  1. There's a pretty good map on the Press-Enterprise web site showing the ozone concentration levels across the IE: