Captive-Air Irradiation Experiments on Ozone Formation in Southern California

Abstract

One phase of an air-pollution study conducted in the Los Angeles basin during the summer of 1987 consisted of outdoor smog-chamber experiments, 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 irradiation experiments conducted on 33 test days are used to obtain empirical models of ozone formation. These fitted models are used to construct ozone contours as a function of the precursor levels, evaluate proposed control strategies intended to reduce ozone levels, and examine the effects of ambient temperature and ultraviolet radiation on the formation of ozone. An unusual aspect of this environmental study is the use of fractional-factorial experiments to guide the selection of the precursor combinations on approximately one-third of the test days.

KEY WORDS:

• Empirical kinetic modeling
• Experimental design
• Fractional factorials
• Measurement-error models
• Ozone formation
• Regression