Test of the theory of ozone generation in Los Angeles atmosphere

Abstract

The extensive chemical and physical measurements of the Los Angeles Reactive Pollutant Program (LARPP), Operation 33, are analyzed to test the suitability of current mechanistic hypotheses related to ozone generation in photochemical smog. The pollutant concentrations and certain physical variables were determined from aircraft observations at various elevations and times within a well-defined air mass which moved across the Los Angeles Basin. Ground-level pollutant concentrations and ultraviolet intensities were also obtained from sites near the track of the air mass. These data, simple theory, and reaction rate constant estimates are utilized to calculate the rate constants for ozone and NO/sub x/ reactions in the atmosphere. Two theoretical models are considered. The first neglects uv light attenuation within the polluted layer and reflected light from the surface of Los Angeles, while in the second model account is taken of both of these factors. The experimental data from observations made later than the 0920 hour are in reasonable accord with the results of the two models, and within the accuracy of the data they confirm the presently accepted ozone formation mechanism.