Effect of chemical kinetics uncertainties on calculated constituents in a tropospheric photochemical model

We have evaluated uncertainties in tropospheric concentrations calculated with a one-dimensional photochemical model, using a Monte Carlo technique to introduce random uncertainty into the model rate coefficients. The most critical reactions turn out to be the primary photodissociations of O₃ and NO₂, which initiate ozone destruction and formation, respectively. The reaction between OH and methane is critical, as is the rate of nitric acid formation, which removes both odd nitrogen (NO_x) and odd hydrogen (HO_x). Species-species correlations reveal anticorrelation between HO_x and NO_x and positive correlation between OH and peroxides, acids, and aldehydes. Several experimental strategies for optimizing the deduction of OH are described, including one based on measurement of the HO₂ radical. -from Authors