Almost Blue Skies in Los Angeles

Los Angeles's notoriously smoggy air is the cleanest it's been in 50 years.

A mile-high wall of mountains that was once obscured in gray-brown haze now pulls sharply into focus, and sunburn warnings have become more common than smog alerts. "You can see the mountains, you can see the trees," marvels Bud Chathan, during a recent afternoon stroll in Pasadena, Calif.

The City of Angels still has the nation's dirtiest air, and pollution could increase again because of the soaring popularity of gas-guzzling light trucks and sport utility vehicles. Nevertheless, all acknowledge 1997 as a landmark for the fewest ozone and health warnings in memory.

"The bottom line is it's the cleanest year," says Joe Cassmassi, a meteorologist for the South Coast Air Quality Management District.

With cars, trucks, and motorcycles generating roughly half the pollution, Richard Varenchik, a California Air Resources Board spokesman, attributes most of the improvement to cooperation from auto manufacturers and tighter emissions controls. "The car built in 1997 emissions-wise is more than 95 percent cleaner than the car from 1970," he says.

Cassmassi says the turnover of old cars and two years of reformulated fuels also cleaned the air. El Nino has helped, too, bringing tropical moisture, cooler weather, and above-normal rainfall that have combined to help scrub the air.