The U.S. Environmental Protection Agency appeared to make great strides this week when it announced new requirements to improve air quality in 474 counties, including eight in Maine. This encouraging step forward, however, will be quickly undone if the agency does not reverse its pattern of giving highly polluting companies and plants more leeway in fouling the air.

Added to the “non-attainment areas” under a new eight-hour ozone standard are portions of Lincoln, Knox, Hancock and Waldo counties. They join Sagadahoc and parts of Cumberland, York and Androscoggin counties, which have been on the non-attainment list for years. The new additions have until 2009 to come into compliance while the other counties have until 2007. However, states to the south and west have more time to clean up, setting up Maine, the recipient of their dirty air, for failure.

With release of the EPA rules it is now up to the states to come up with plans to meet them. The Maine Department of Environmental Protection is already working on or has completed rules to reduce emissions from marine engines, paints, solvents and degreaser, gas cans and other sources. Although these are all helpful, they don’t address the real sources of pollution that Maine has been battling for years – dirty power plants in other parts of the country.

Because the EPA has failed to enforce clean air regulations, Maine has joined several other states, mostly in the east, in court cases to get the plants to clean up. At the same time, however, the Bush administration has weakened rules dealing with mercury and other pollutants from these facilities.

EPA Administrator Michael Leavitt is talking like that may change with regard to ozone. His comments are hopeful.

“A strong national approach is needed because many states believe they could take all their cars off their roads, clean up the power plants and close factories in their state, and they will still fail to reach attainment,” Mr. Leavitt said during a speech at the National Press Club Wednesday.

Put Maine in that category. With regard to ozone, between 75 and 90 percent of the pollutants that contribute to this problem come from outside Maine’s borders, according to the DEP. The state’s highest ozone levels are recorded along the coast.

Ground-level ozone is formed when pollutants from cars, power plants, factories and other sources react with sunlight. The two groups of pollutants involved are nitrogen oxides (NOx) and volatile organic compounds (VOCs).

VOCs are primarily emitted from burning coal, oil and gasoline. They also come from evaporation of gasoline, solvents, cleaners and paints. The primary sources of NOx are motor vehicles (49 percent), electric utilities (27 percent), and other industrial, commercial and residential sources that burn fuels, according to the EPA. The agency adds that the pollutant can be transported over long distances, typically following the prevailing winds. That means much of it ends up in Maine.

All this means that if Maine were to dramatically reduce in-state emissions, which it should strive to do, the air here would still be polluted with NOx and VOCs coming from other parts of the country. The state’s efforts, however, to get power plants in other states to meet clean air requirements have either failed or been tied up in court.

So, while announcing tougher rules is a good thing, they are meaningless if they are not followed up with tough enforcement actions against the worst polluters.