CAPTIVE-AIR IRRADIATION EXPERIMENTS ON OZONE FORMATION IN SOUTHERN CALIFORNIA

One phase of an air-pollution study conducted in the Los Angeles basin during the summer of 1987 consisted of outdoor smog-chamber experimen ts, called captive-air irradiation experiments, intended to study the response of ozone to changes in its main precursors, hydrocarbons and oxides of nitrogen. In this article, a total of 249 captive-air irradi ation experiments conducted on 33 test days are used to obtain empiric al models of ozone formation. These fitted models are used to construc t ozone contours as a function of the precursor levels, evaluate propo sed control strategies intended to reduce ozone levels, and examine th e effects of ambient temperature and ultraviolet radiation on the form ation of ozone. An unusual aspect of this environmental study is the u se of fractional-factorial experiments to guide the selection of the p recursor combinations on approximately one-third of the test days.