S.D. Had Second-Worst Ozone Levels in Nation, EPA Figures Indicate

San Diego had the second-worst incidence of high ozone levels in the nation during the three-year period ending in December, 1986, according to Environmental Protection Agency figures released Thursday.

But the figure pales by comparison with ozone levels in Los Angeles, which easily led the nation, and San Diego officials blamed “transport” smog from Los Angeles for San Diego’s high rating.

The EPA considers the air unhealthy if the average pollution level during one hour goes above .12 units of ozone in 1 million units of air.

Recent health studies suggest that even that level may be too high, but on the worst smog days in Los Angeles ozone levels reach .35 units per million, about three times the EPA standard.

Exceeded Standard 11 Days

In the past three years, the EPA said San Diego had an average of 11 days a year during which it exceeded the federal ozone standard, compared with 154 for Los Angeles, 29 for Bakersfield, 21 for Fresno, 19 each for New York City and Houston, 14 for Connecticut and 12 for Modesto.

To figure the high ozone level figures, the EPA took the fourth highest ozone level reading in 1984-1986 for a given area, disregarding the first three to make allowances for weather or other conditions, such as fires, that would affect the ozone level.

On that day, San Diego’s ozone levels reached .22 units per million, the EPA found. However, the San Diego County Air Pollution Control District said that without Los Angeles’ air pollution traveling down the coast, San Diego’s ozone level would have been .15 units per million, according to Lynn Eldred, the district’s public information officer.

“San Diego would be ranked 22nd in the nation (in ozone level) if you just accounted for locally generated pollution,” Eldred said. “But of course they’ll find much higher concentrations here in San Diego because of Los Angeles’ pollution.”

She said by studying air at certain monitoring stations, the district was able to determine with reasonable certainty the amount of air pollution San Diego receives from the Los Angeles air pollution control district, which includes Orange County.

“Del Mar is a good place to track transport air because the station is one block from the ocean,” she said. “The only place the smog could have originated from is outside the San Diego air basin, because the air blows in from the ocean, it doesn’t blow out.”

“People do have to breathe transport pollution just as if it was generated here in San Diego, so of course it is still a health concern,” Eldred said. “But it is something we can’t control here in San Diego. When they (Los Angeles) make more progress, you’ll see changes in San Diego.”

So far, air quality in Los Angeles in 1987 has been unexpectedly good, far better than the EPA estimates would indicate, said Ron Ketchum, spokesman for the South Coast Air Quality Management District. Much of the difference is a result of weather patterns that hurt last year’s air quality but improved this year’s, he said.

Nevertheless, Ketchum said, despite some “remarkable improvements” in some parts of the Los Angeles basin, “the bottom line is we’re still far from meeting the standards.”

The new figures emphasize the difficulties involved in reducing ozone, the major component of smog and a serious health threat that can cause immediate and long-term damage to human lungs.

On another smog component, carbon monoxide, a pollutant closely associated with engine exhausts, the new figures indicate substantial progress. In this category, pollution levels were one-third lower in Los Angeles than those reported last year, indicating an impact by emission controls.

While ozone interferes with breathing, carbon monoxide’s ill effects center on the heart, causing chest pains in sensitive individuals.

Nationally, the figures show some improvement in ozone and carbon monoxide levels.

The EPA reported 65 cities with unhealthy carbon monoxide levels, down from 91 last year. Denver, where thin, mountain air makes car engines burn dirtier, heads this year’s list. Los Angeles’ carbon monoxide levels ranked second worst.

Problem ‘Getting Worse’

In the ozone category, the number of areas with unhealthy air declined to 62 this year from 76 reported last year.

But Rep. Henry A. Waxman (D-Los Angeles) said that “the pollution problem is getting worse,” 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 plans hearings next month on bills to extend and strengthen the Clean Air Act.