Rise in Smog Alerts Blamed on Weather : Environment: After two years of improvement, the L.A. area’s air quality has declined. But the long-term trend is positive, AQMD officials say.

Reversing two years of diminishing summer smog levels, air pollution is worse this year in the Los Angeles region, and the culprit seems to be the weather, air quality authorities said Thursday.

First-stage smog alerts had been issued 33 times as of Wednesday, compared to 21 last year by Aug. 19. Moreover, the region has exceeded the federal health standard for ozone pollution on 96 days, compared to 70 days during the same January-through-Aug. 19 period last year.

A first-stage smog alert is called when the ozone level reaches 0.20 parts per million for one hour or more. The federal health standard is 0.12 p.p.m.

Ozone is a toxic pollutant at ground level and is a major component of smog that can cause respiratory problems, hamper the body’s immune system and damage plants. At high altitudes ozone shields the Earth from harmful ultraviolet rays of the sun.

For the 13 million residents of the four-county South Coast Air Basin, the news announced Thursday by the South Coast Air Quality Management District probably comes as no surprise. Los Angeles, Orange, Riverside and San Bernardino counties have blistered under a summer heat wave for the last 11 days. An ugly gray-brown pall has hung over much of the basin.

Blame was placed on a persistent high-pressure ridge that has set up a strong inversion layer--an atmospheric condition in which a mass of warm air moves in over a mass of cooler air and acts as an invisible lid preventing pollutants from escaping upward. The high pressure has also caused winds to die down.

“We’ve been essentially primed for a strong smog period,” AQMD senior meteorologist Joe Cassmassi said.

AQMD Executive Officer James M. Lents said, “We’ve had more days with very unhealthful air than at this point last summer.” He said the last time stage-one alerts were as numerous was in 1989, when 105 such warnings were issued by Aug. 19.

Nonetheless, Lents said that the long-term trend shows overall improvement in the quality of air, thanks to increasingly stringent smog controls on vehicles and businesses.

“People look outside and they say, ‘You’re crazy. This air quality is awful!’ Yes, this air quality is awful. But we’re speaking relatively,” Lents told reporters.

“We believe the health of this community is in much better shape than what it was a decade ago. On any individual day, any individual summer, weather will cause air pollution levels to rise or fall some amount,” he said. “But over the years as it averages out . . . people are breathing healthier air. That doesn’t mean they are breathing healthy air.”

As proof, Lents said that even though this year comes close to matching the number of days that the federal ozone standard was exceeded in 1989, the violations did not last nearly as long--2,890 hours this year, compared with 4,326 hours in 1989.

Thursday’s report came as representatives of major cities along the Pacific Rim met at the AQMD’s Diamond Bar headquarters to exchange information on how “megacities” can deal with smog.

The specialists are from Bangkok, Thailand; Jakarta, Indonesia; Kuala Lumpur, Malaysia; Los Angeles; Manila; Mexico City, Singapore and Taipei.

Sergio Sanchez-Martinez, director of environmental studies for Mexico City, said results of a comparative case study on vehicular pollution in the cities will be announced next February in Jakarta.

In general, he said, there is agreement on the need for cleaner fuels and vehicles, promotion and development of alternative fuels, more stringent regulations, traffic control and improved mass transit. But, he said, there are formidable political and financial problems to overcome.

The workshop and conference are sponsored by the Mansfield Center for Pacific Affairs based in Missoula, Mont., and the World Environment Center, based in New York.

SMOG ALERTS IN THE SOUTHLAND

Here are the number of days each year that the South Coast Air Quality Management District had first- and second-stage smog alerts, and the number of days state and federal ozone standards were violated. The district includes all of Los Angeles, Orange, and Riverside counties and portions of San Bernardino County.

OZONE LIMITS * State standard: 0.09 p.p.m. * Federal standard: 0.12 p.p.m. * First-stage smog alert: 0.20 p.p.m. * Second-stage smog alert: 0.35 p.p.m. * Third-stage smog alert: 0.50 p.p.m. p.p.m. = parts per million

1st-stage 2nd-stage Days exceeding Days exceeding Year alerts alerts federal standards state standards 1976 102 7 194 237 1977 121 11 208 242 1978 116 23 187 217 1979 120 17 191 226 1980 101 15 167 210 1981 99 5 167 222 1982 63 2 149 191 1983 84 3 152 190 1984 97 0 173 207 1985 83 7 158 206 1986 79 1 164 217 1987 66 0 160 196 1988 77 1 178 216 1989 54 0 157 211 1990 41 0 130 184 1991 47 0 130 183 1992* 33 0 96 128

* Jan. 1-Aug. 19 Source: South Coast Air Quality Management District