UCI scientists find chlorine may contribute to ozone formation

Study discovers evidence of reactive chlorine chemistry in Southern California surface air

Irvine, Calif., June 13, 2006

Standard methods of predicting air pollution don’t take atmospheric chlorine into account, but the chemical could be responsible for 10 percent or more of daily ozone production in local air, research at UC Irvine has found.

Air measurements taken nearly nonstop in the Irvine area over a two-month period showed that daytime chlorine gas levels typically measured five parts per trillion or less, but occasionally reached as high as 15 parts per trillion. Observation of daytime chlorine is surprising because chlorine molecules break apart just minutes after entering the atmosphere and being exposed to sunlight.