Effect of Nitric Oxide on Photochemical Ozone Formation in Mixtures of Air With Molecular Chlorine and With Trichlorofluoromethane

摘要

An experimental and theoretical study was made of ozone (O3) formation in air containing either molecular chlorine (Cl2) and nitric oxide (NO) or trichlorofluoro-methane (CFCl3) and NO. The purpose of this work was to study the NOx) and ClOx mechanisms for O3 destruction. Similar mechanisms have been proposed for 03 destruction in the stratosphere by NO and CFCl3. Mixtures of these gases in air were photolyzed at room temperature and atmospheric pressure by ultraviolet, simulated solar radiation. Concentration- against-time profiles of O3, NO, and NO2 were measured. A temporary rise in O3 concentration was observed for both CL2-NO-air and CFCl3-NO-air mixtures. Ozone concentration then-decreased and, in the case of CFCl3-NO-air, stayed close to zero during the entire 3- to 4-hour reaction. A chemical mechanism that satisfactorily explains the experimental results was developed with the aid of a general chemical kinetics computer code. Computations show that the experimental O3 concentration behavior is explained by the formation and subsequent destruction of chlorine nitrate (C1ONO2).