Science: Villainous California Sun

Dirt and grime alone are not responsible for Los Angeles' notorious, eye-stinging smog. The real villain is Southern California's much-touted sunshine, reports the Stanford Research Institute after a seven-year study.

In the stagnant air over the mountain-hemmed area, ordinarily harmless chemicals rise from factory chimneys, auto exhausts, backyard incinerators at the rate of 3,100 tons a day. Under strong sunshine, the chemicals react with one another and with molecules of ozone (O₃) to form a low-hanging, acrid pall, irritating to humans and damaging to crops.

Stanford's researchers have yet to discover exactly how ozone is formed. But they believe that it results from a photochemical reaction of sunlight and unknown materials in the air. Furthermore, as ozone increases, so does smog. Los Angeles' sunshine has made the atmosphere the most ozone-laden in the world: as high as 80 parts per 100 million parts of air. The solution to the Los Angeles smog problem, according to the Stanford scientists: find out which materials react with the sun to form ozone, filter them out before they reach the open air.

Continuing where the Stanford researchers left off, the Los Angeles area last week was launched on its biggest, most desperate smog investigation. For three months, during the height of the smog "season," scientific teams will analyze some 700 air samples each day at ten different sampling stations spread through the area, will attempt to discover exactly what causes smog to form and how it spreads its grimy pall across the landscape. Cost of the investigation: $300,000.