Yet another study has found that breathing dirty air is bad for your health. But don’t expect the government to improve the situation. The best you can do is to change your habits, drive less for example, to reduce your contribution to this growing problem.

High above the planet in the stratosphere ozone protects the Earth from the sun’s dangerous ultraviolet rays. At ground level, however, it is a dangerous gas that has been linked to breathing and heart problems. Pollutants from cars and smokestacks mix with sunlight to become ozone.

The study, published in the current issue of the Journal of the American Medical Association, found that increases in ozone levels led to an increased number of deaths from cardiovascular, respiratory and other causes. According to a review of 14 years’ worth of data, death rates increased 0.52 percent on days when the ozone count during the previous week had risen by 10 parts per billion. The increase was even higher

– 0.64 percent – when looking at only cardiovascular and respiratory events.

The researchers reviewed mortality data, collected by the federal government, for 95 urban areas, accounting for about 40 percent of the total population from 1987 to 2000. The study was funded by the U.S. Environmental Protection Agency.

That does not mean the EPA supports its conclusions or will do much about them.

Earlier this year, the agency added portions of four more Maine coastal counties to a national list of counties that fail to meet ozone requirements. These counties are home to no large cities or manufacturing facilities.

That’s because between 75 and 90 percent of the pollutants that contribute to this problem come from outside Maine’s borders, according to the Department

of Environmental Protection. Even if Maine were to dramatically reduce in-state emissions, which it strives to do, the air here would still be polluted with ozone precursors coming from other parts of the country. To combat this problem, EPA Administrator Michael Leavitt has said he plans to move ahead with the Clear Air Interstate Rule, which would use a cap-and-trade system to reduce target pollutants from power plants by 70 percent by 2025.

However, the rule has yet to be finalized and does not address other pollution sources. In addition, Maine’s efforts to get power plants in other states to meet current clean air requirements have either failed or been tied up in court.

Rather than cracking down on the highly polluting coal-fired power plants in the Midwest and South, the Environmental Protection Agency has written the rules to make them more lenient. These plants, grandfathered under the Clean Air Act because it was assumed they would be shut down by now, continue to spew huge amounts

of mercury, sulfur dioxide, nitrogen oxides and other pollutants that are carried to Maine by the prevailing winds. A rule requiring them to add new pollution control equipment when making major upgrades was canned by the Bush administration.

The conclusion of the study was clear: “Reducing such ozone pollution by about 35 percent on any given day could save about 4,000 lives a year across the country.” Those lives should be saved as soon as possible.