HOUSTON — Civic leaders want to clear the air about Houston's label as the nation's smoggiest city — they've taken another look at the data and say Los Angeles deserves the dishonor.
Harris County officials announced their findings Thursday using a study that indicated some air-polluting emissions were showing up at lower levels than in previous reports.
According to preliminary federal data released last year, the city for the first time had more dirty-air days than Los Angeles. The Environmental Protection Agency said Houston recorded at least 50 days in 1999 in which it exceeded federal health standards for ozone, a component of smog.
County officials conceded Thursday that Houston's ozone level is still too high to comply with the federal Clean Air Act, but said the air in Los Angeles has excessively high levels of particulate matter and carbon dioxide as well as ozone, making it the country's smoggiest.
Paul Bettencourt, the county's tax assessor, led the latest study, which put smog-producing nitrous oxide emissions at 7 percent lower than previous readings. It analyzed the number and type of registered vehicles in the eight-county Houston area, after Bettencourt realized previous studies had not included counts of the number of cars on the roads.
Earlier studies used traffic counts and predictions of vehicle numbers, he said.
"It was just guesswork," Bettencourt said. "It was people standing on the corner counting cars."
Texas Natural Resource Conservation Commission officials said the latest findings won't keep them from imposing restrictions on Houston drivers in a campaign to clean up the city's air.
The agency's three-member commission will meet in August to decide what measures to put in place, which could range from a speed limit of 55 mph to restricting car use to alternate days.