L.A. Still Has Worst Ozone Level in U.S., Study Finds

The Los Angeles region continued to lead the nation last year with the highest level of ozone, the major component of smog and a serious health threat, and had the second-worst concentration of carbon monoxide pollutants, according to figures released Thursday by the U.S. Environmental Protection Agency.

Ron Ketchum, spokesman for the South Coast Air Quality Management District, said parts of the Los Angeles Basin have shown some “remarkable improvements,” but he added: “The bottom line is we’re still far from meeting the standards.”

The EPA considers the air unhealthy if the average pollution level in one hour goes above 0.12 units of ozone in 1 million units of air, and recent health studies suggest that even that level may be too high. In the last three years, Los Angeles ozone levels have reached as high as three times the EPA standard,

San Diego County had the second-worst ozone reading in the country, the EPA figures show, roughly twice the agency standard. But there, like other areas with smog problems, ozone is a far more sporadic problem than in the South Coast Basin, which includes Los Angeles, Orange County and non-desert portions of Riverside and San Bernardino counties.

Exceeded Standards

In the last three years, San Diego had an average of 11 days a year during which it exceeded the federal ozone standard, compared to 154 for Los Angeles, 29 for Bakersfield, 21 for Fresno and 19 each for New York City and Houston.

Nationally, the figures show improvement in ozone and carbon monoxide levels. In the ozone category, the number of areas reported to have unhealthy air declined to 62 last year from 76 reported in 1985.

Carbon monoxide levels showed substantial progress as pollution levels dropped to one-third lower than those reported the previous year, indicating an impact by emission controls. The EPA reported 65 cities with unhealthy carbon monoxide levels last year, down from 91 in 1985.

Denver, where thin mountain air makes car engines burn dirtier, heads the new list. Los Angeles was the worst in this category the year before.

Rep. Henry A. Waxman (D-Los Angeles) said “the pollution problem is getting worse” in 1987, citing the hot, dry weather over most of the country this summer.

“The need for legislation is clear,” said Waxman, who chairs the House Energy and Commerce subcommittee on health and the environment, which will hold hearings next month on bills to extend and strengthen the Clean Air Act.

The new figures emphasize the difficulties involved in reducing ozone, which interferes with breathing and can cause immediate and long-term damage to human lungs. The harmful effects of carbon monoxide, a pollutant closely associated with engine exhausts, center on the heart, causing chest pains in sensitive individuals.

The Los Angeles area has led the nation in ozone pollution for many years. The region also consistently has been among the leaders in carbon monoxide pollution.

The latest EPA figures are based on air quality monitoring from 1984 through 1986.

In another development, researchers from around the world Thursday resumed the biggest study of the Los Angeles Air Basin’s smog makeup in 15 years.

The Southern California Air Quality Study, originally scheduled to end July 26, was suspended because of unseasonably cool weather and the lowest early season smog levels in 30 years.

The California Air Resources Board said the study has been restarted for the next two weeks when researchers believe that more typical smog levels and weather conditions will return to the region.