A numerical analysis with sensitivity analysis on diurnal cycle of NOx and O3 was investigated to specify prime reactions with high impact on O3 deplations by emissions of exhaust gases. NOx concentration was measured in a vaccum chamber with emission of low-pressure mercury lamp, and numerical analysis of reactions in the chamber was conducted. Fifth-order BDF method was employed to calculate ordinary differential equations of concentrations and sensitivities. Reactions with high sensitivity for O3 concentration were limited, and chemical kinetics used in this calculation express history of NOx concentrations correctly in the chamber. This chemical kinetics was applied to the calculations of diurnal cycle of O3 concentration in stratosphere. As a result of this study, prime reactions with high sensitivities on O3 concentration is specified and history of concentrations of NOx, HOx and Ox was derived. Characteristics of NOx, HOx and Ox chemistry in the stratosphere was specified.
