Report: Calif. Areas Have Worst AirMay 1, 2002 | Associated Press The four smoggiest metropolitan areas in the nation are in California, according to an annual American Lung Association report released Wednesday.
The Los Angeles area — including Riverside, Orange and San Bernardino counties — tops the list for the third straight year, followed by Bakersfield, Fresno and the Visalia-Tulare-Porterville areas. The Houston metro area was fifth.
"This report is really focused on ozone pollution as a national problem, but we're most famous for it in California," said Dr. John Balmes, president of the association's medical section.
The report is based on Environmental Protection Agency data from 1998-2000 measuring the number of days that pollution exceeds the EPA's air quality index for ozone, commonly called smog. It did not take into account improvements in the past year.
Smog has been reduced by two-thirds in California during the past two decades, but much work remains. The Los Angeles area has made the most progress, cutting smog by 75 percent since 1985, but officials still do not foresee the city meeting federal standards until 2010.
Ozone pollution forms when emissions from fuel combustion combine with sunlight, creating a chemical reaction that chokes the air and leaves a brown haze visible on the horizon. California's smog is worsened by the state's dense population and a topography that traps air pollution.
"There's been real progress, but it's a tough battle," said Richard Varenchik, deputy communications director for the California Air Resources Board.