The second pollutant covered by the new EPA proposal is ozone -- a molecule made of three oxygen atoms (most oxygen molecules in the air have two oxygen atoms). This highly reactive molecule is a powerful respiratory irritant at levels frequently found in cities during summer. It can cause shortness of breath, chest pain when inhaling deeply, and wheezing and coughing.
Ozone is made when sunlight acts on hydrocarbon (defined) pollutants in the air. Thus the way to control it is to reduce the amount of hydrocarbons in the air. These hydrocarbons are spewed out by autos, trucks, and such industrial processes as painting, oil refining and chemical manufacture.
Is ozone good or bad? That depends on where it is...
Important: while ground-level ozone is a problem, stratospheric ozone is a blessing, a shelter against punishing ultraviolet rays from the sun. The stratospheric ozone layer is being attacked by chlorine atoms carried aloft in chloroflourocarbon chemicals that are widely used as refrigerants and cleaners. Three years of data from NASA's Upper Atmosphere Research Satellite provide conclusive evidence that synthetic chlorine products in the stratosphere are causing the Antarctic ozone hole. Here's a great page explaining what's known about the stratospheric ozone that allows life to live.
Meanwhile, back on Earth
In all this discussion of air pollution, it's important to remember that we share the planet with other life. These satellite-generated maps show changes in Norway's nature due to air pollution.
And little, overlooked lichens (defined) are also suffering from air pollution, according to research by James Bennett of the U.S. National Biological Service (see "The Miner's Canary" in the bibliography).
Enough bad news.
The new EPA rules would reduce the limit of ground-level ozone from 120 parts per billion (ppb, measured over one hour) to 80 ppb, measured over eight hours. Although reduced, this level is well above average for cities: Minneapolis/St. Paul, for example, has an average of 26 ppb, and Sao Paulo, Brazil averages 12.5 ppb. And one isolated infraction would not trigger penalties, as the EPA explained: "with the average fourth highest concentration over a three-year period determining whether an area is out of compliance." The Lung Association, for one, thinks the new level is still too high.
How on Earth can we detect air pollution faster, cheaper and more accurately?
