Smog Season Ends With 41 Stage 1 Alerts--a Low Total : Environment: Mild summer contributes to cleaner air. Numbers have dropped 47% since 1988.

Tying 1990 for the cleanest skies on record, Southern California’s smog season ends today with 41 smog alerts--continuing a decade-long trend of slow, steady improvement in the nation’s most polluted area.

Much of the decline in 1992 is a testimonial to the summer’s mild weather, especially in June and early July. Many of the Stage 1 health alerts for ozone in the Los Angeles Basin were congregated during an unusual bout of summery conditions in late April.

“We had a very bad April. If we hadn’t had that spell of hot weather and stagnant air, it might have been a record clean year,” said Bill Kelly, spokesman for the South Coast Air Quality Management District.

From the mountains to the coast, days in which ozone reached Stage 1 concentrations dropped 47% from 77 days in 1988 and 65% from 117 days in 1978, according to AQMD data. The 41 days of health alerts this year and in 1990 are the fewest recorded in about 40 years of air pollution monitoring.

The most impressive gains were in parts of the Inland Empire, particularly Riverside and Redlands, which dropped to eight alerts compared to twice that number in 1991.

But there was bad news, too. The basin violated the federal health standard for ozone on more days--140 compared to 125 last year. That means although air pollution on many days was not severe enough to trigger full-scale alerts, it often hovered at concentrations just below that point, enough to be considered unhealthful under national standards.

The increase in violations puts even more pressure on the Los Angeles Basin to meet federal mandates to clean its air. The region still has, by far, the nation’s worst air pollution, and has consistently violated Clean Air Act standards for more than 20 years.

The recession, however, has put unprecedented political pressure on the AQMD to delay or weaken its regulations on businesses and industry.

“It’s certainly no time to sit back and say we can ease off now,” said Jeff Hill, executive director of the Coalition for Clean Air. “Every effort we can make for reducing emissions is still necessary.”

Ozone, Southern California’s most hazardous and persistent air pollutant, typically peaks May 1 through Oct. 31. During Stage 1 alerts, people are advised to curtail outdoor activity.