Fewer Americans have had to breathe unhealthy levels of smog or microscopic soot in recent years, but air pollution remained a threat in counties where more than half the nation lives, the American Lung Association said in an annual report Thursday.
Using data from the U.S. Environmental Protection Agency, the group found that the number of counties in which unhealthy air was recorded fell significantly for the first time in six years, to 390 from 441 in last year’s report. The new report covered 2001 to 2003, while the previous one analyzed pollution levels from 2000 to 2002.
The association attributed the dip to cool and wet weather in the years studied, government controls on Eastern coal-fired power plants and improved vehicle emissions standards. Areas of the Southeast accounted for much of the drop in pollution.
But Janice Nolen, the group’s director of national policy, emphasized that the counties where problems persist are home to 152 million people, or 52 percent of the U.S. population.
“People’s lives are shortened by months to years because of the air they’re breathing,” she said. “The trend has gotten a little bit better in the last few years ... but we’re not out of the woods.”
Counties were considered to have unhealthy air if their pollution levels exceeded federal standards for an average of about three days a year.
Most of the violations were for ground-level ozone, a precursor to smog that causes respiratory illnesses that can be especially harmful to the elderly, children and people with asthma. Ozone pollution occurs when hydrocarbons and nitrogen oxides — released when fossil fuels burn or chemicals evaporate — combine with heat and sunlight.
California remains the nation’s ozone capital, with nine of the top 10 most smog-choked counties. San Bernardino County had the worst smog.
One in five Americans, meanwhile, face year-round unhealthy exposure to particulates, tiny soot from diesel-burning trucks, fireplaces, agriculture and other sources, the report found. It can lodge deep in the lungs and contribute to heart problems.
While the five most soot-polluted counties are also in the Golden State, five counties in Ohio and three in Pennsylvania also were among the 25 worst.
The EPA credited tougher standards for the drop in air pollution, including its 1998 rule requiring Eastern states to reduce power plant nitrogen oxide emissions. Impending emissions standards for trucks, cars and sport-utility vehicles will help cut pollution further, the agency said.
Conservatives and energy-industry groups have criticized the Lung Association’s methodology, saying it’s misleading to give counties “failing” grades for air pollution that might have been recorded at just one monitoring station.
“I wish they would do more informing and less scaring,” said Ben Lieberman, a senior environment and energy policy analyst at the Washington-based Heritage Foundation, a conservative research group.
