STORY: Birmingham-area officials continue to struggle to control ground-level ozone under the threat of EPA sanctions -- which could cost the state highway funds, jobs, and other economic development. But even if everyone followed instructions to avoid drive-through lanes, mow lawns and refuel cars only after 6 p.m., that would only address part of the problem.
WHAT: The biggest factor, the one that can't be controlled, the one that can make ozone even from the hydrocarbons naturally released from trees, the factor most responsible for reducing ozone emissions, is the weather. And the government standards, properly aimed at trying to reduce a credible health threat, are nevertheless nearly impossible for growing communities to meet.
WHO: George Hidy, Ph.D., professor of civil and environmental engineering in the UAB School of Engineering. Call Hidy at 205-934-8499.
WHY: Sunshine and winds not strong enough to move pollutants out of the area are major factors. The sun creates ozone by chemically activating the nitrogen oxides from fossil fuel combustion. That creates a chain reaction with unburned gasoline from motor vehicles and from turpentine-like hydrocarbons from vegetation. Add community growth and development to the mix - bringing more hydrocarbons and nitrogen oxides into the area - and it becomes maddeningly difficult for places like Birmingham to meet EPA-mandated clean-air requirements.
Besides that, a community is out of compliance with national air quality standards for ozone if it exceeds an extremely low ozone concentration (based on parts per million) in the air at any point on a given day. Other pollution standards are based on an average concentration instead of the extreme. Trying to meet such a target is nearly impossible, Hidy said. A tougher air quality standard mandated in 1997 is being challenged in court, even while many communities struggle to meet the old one.
HOW: Reducing emissions is obviously the path to follow, Hidy said, but with the weather such an important factor, defining good air quality can best be addressed by creating a realistic, statistically based ozone standard that addresses both health concerns and the fact that you can't change the weather.
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