YOU ARE HERE: LAT HomeCollections

Southland Smog Levels Are Lowest in 4 Decades : Pollution: Stage-one alerts drop to 13, compared to 23 last year. But region's air remains nation's dirtiest.


This year's smog season has ended as the best in four decades for Southern California, an encouraging note as officials struggle to decide how best to fight the last crucial battles in the campaign for clean air.

Although the region's smog has steadily improved over the last 20 years, especially in the 1990s, this year stands out as exemplary in numerous ways, according to data released Friday.

Just 13 stage-one alerts for ozone, the Southland's predominant pollutant, were reported by the South Coast Air Quality Management District during the unofficial smog season that ended this month. That compares with 23 last year and 83 a decade ago. Alerts--which signal that air is so unhealthful that everyone is warned to avoid prolonged exposure outdoors--declined this year by 43%.

Just as notably, the peak amount of ozone polluting the region's air dropped to the lowest level in decades, and the number of health advisories and violations of a key federal standard declined substantially.

Despite the good signs, smog officials repeated their normal refrain that we have come a long way but have far to go. The four-county Los Angeles Basin, and the eastern San Gabriel Valley in particular, retained its long-held claim to the nation's worst air pollution. No other metropolitan region even came close.

"It's a huge improvement, it really is, and it's encouraging that all the data shows we're still going in the right direction," said AQMD senior meteorologist Joe Cassmassi. "But when you flip back to looking at how many times we've violated the health standard, it still makes this the dirtiest community in the nation."

Ozone pollution was still serious enough to violate federal health standards on 91 days--an average of nearly once every three days. The year's highest concentration, measured in the Glendora area, was the lowest peak level on the region's books, but was double the amount deemed safe under the federal health standard.

Medical officials say that during such violations people with respiratory or cardiac problems face serious health risks.

"We applaud the progress," said Linda Waade, executive director of the Coalition for Clean Air, a Santa Monica-based environmental group. "But we can't forget we're only halfway there."


AQMD meteorologists say reduced emissions from vehicles and industry, not favorable weather, explain this year's improvement.

According to their calculations, if the same weather conditions of this past June through August had occurred when emissions were as high as in 1982, the Southland would have suffered about 80 smog alerts.

The pollutants that form ozone have dropped 25% to 30% since the mid-1980s due to new pollution controls on vehicles and industry as well as the economic recession.

This summer's weather conditions were fairly typical, with warm temperatures and inversions that brought some smog bouts in late June, July, August and early September. Ozone, a potent invisible gas, is formed when hydrocarbons and nitrogen oxides react on sunny days when the air is still and pollutants are held close to the ground by a strong inversion layer.

Ironically, Southern California suffered a siege of poor air on Thursday and Friday, although a different pollutant, particulates, is to blame for the thick film of murky air.

During the last two days, health alert levels were reached for particulates, the microscopic grains of vehicle pollution and dust that turn skies gray and block visibility. Health officials believe the small particles lodge in lungs and contribute to sometimes fatal respiratory health problems. A persistent inversion and a wind pattern circulating moist air have exacerbated the particulates this week.

For the region's most notorious pollutant, ozone, Cassmassi predicts that stage-one alerts will finally vanish here around the turn of the century. The AQMD and state Air Resources Board a year ago adopted a plan containing dozens of proposed rules designed to achieve the health standard by 2010.

But that goal can only remain within sight, air quality officials stress, if new anti-smog rules are enacted over the next 15 years, since population growth could reverse the gains.

Local and state air quality officials face mounting pressure to give economic concerns more weight in decisions on anti-smog regulations, including California's controversial electric car mandate and pollution limits for local factories.

The latest sign came Thursday when the AQMD revised an earlier proposal to regulate volatile organic compounds, or hydrocarbons, at nearly 1,000 industrial plants that use large amounts of high-polluting solvents, paints and other chemicals.

Los Angeles Times Articles