Conditions: Where the Air Is Unfair
By Mark Jannot

Ventura, home of lemon groves, California surf, and Patagonia Inc. headquarters, is also on the U.S. Environmental Protection Agency's air-quality hit list. Ever since amendments to the Clean Air Act were passed in 1990, unexpected burgs like Ventura have shown up right alongside big cities on the EPA's ozone-detecting radar: Whenever an area's ozone level averages over 0.12 parts per million for at least one hour of one day per year over a three-year period, it's said to be "out of attainment" with air standards. The agency goes on to rate the ozone danger in these out-of-attainment areas; on any day when a city earns one of the three most critical classifications--serious, severe, and extreme--its air represents a genuine health risk for those of us who like to spend extended amounts of time outside. Here's a partial list of this year's worst offenders, along with each city's fourth-highest recorded ozone level (the EPA uses that figure to avoid classifying cities on exceptionally bad ozone days) over a three-year period and the average number of days per year that the city is out of attainment. If you live in or plan to visit any of these places, you'll want to strategize before you exercise.

EXTREME
Los Angeles
Ozone Level * 0.33
Days Out of Attainment** 137.5

SEVERE
Houston/Galveston
Ozone Level * 0.22
Days Out of Attainment** 12.2

New York/Northern New Jersey/Long Island
Ozone Level * 0.20
Days Out of Attainment** 17.4

Chicago
Ozone Level * 0.19
Days Out of Attainment** 13

Baltimore
Ozone Level * 0.19
Days Out of Attainment** 8.8

Philadelphia
Ozone Level * 0.19
Days Out of Attainment** 8.8

Milwaukee
Ozone Level * 0.18
Days Out of Attainment** 9.8

Ventura County, CA
Ozone Level * 0.17
Days Out of Attainment** 38.8

SERIOUS
Boston
Ozone Level * 0.17
Days Out of Attainment** 10

El Paso, TX
Ozone Level * 0.17
Days Out of Attainment** 7.9

Springfield, MA
Ozone Level * 0.17
Days Out of Attainment** 6.7

Portsmouth, NH
Ozone Level * 0.17
Days Out of Attainment** 5.3

Washington, DC
Ozone Level * 0.17
Days Out of Attainment** 5.3

Atlanta
Ozone Level * 0.16
Days Out of Attainment** 9.3

Providence, RI
Ozone Level * 0.16
Days Out of Attainment** 6.4

Baton Rouge
Ozone Level * 0.16
Days Out of Attainment** 4.5

Beaumont, TX
Ozone Level * 0.16
Days Out of Attainment** 3.7

*Fourth-highest level recorded over a three-year period in parts per million
**Annual average