WASHINGTON (AP) - Automobiles and small trucks account for less than a third of smog-causing air pollution in major cities, the American Automobile Association said Tuesday, arguing that future pollution controls should be aimed elsewhere.
The AAA, a leading advocacy group for motorists, said a study of air pollution in 24 major cities shows that more than 70 percent of the chemicals that cause smog come from factories, utility smokestacks, refineries and other stationary sources.
Tougher air pollution controls are expected to be imposed by states and local communities in the next few years to comply with new federal air quality standards and to deal with the problems of pollution that drifts across state lines.
The Environmental Protection Agency already has indicated that it intends to pursue tighter pollution controls on coal-burning power plants and some factories, both high emitters of nitrogen oxide, a component of smog. But some additional tightening of emissions from automobiles has not been ruled out.
James Kolstad, AAA's vice president for public and government relations, said the air pollution study conducted for AAA by a private consultant shows automobiles "are falsely portrayed as major causes of smog in our cities." He maintained cars should not be targeted for further pollution controls.
The study showed that in cities such as Atlanta, Baltimore, Washington D.C., Cleveland, and San Francisco, 75 percent to 85 percent of smog-causing pollution - volatile organic compounds and nitrogen oxide - come from sources other than automobiles.
The study said that in the 24 cities studied, nitrogen oxide emission from automobiles were cut by 33 percent between 1970 and 1996, while releases from other sources increased by 16 percent during the same years.
Emissions of volatile organic compounds from automobiles were cut by 79 percent between 1970 and 1996, while emissions from other sources were reduced by 24 percent, according to the study.
"Nobody challenges the idea that proportionately the automobile industry has reduced its emissions dramatically," said Mike Shanahan, a spokesman for the American Petroleum Institute. But he said oil refineries and others also are "under the same mandate to reduce pollution ... and have been doing so."