Evaluation of two MCM v3.1 alkene mechanisms using indoor environmental chamber data

摘要

Photo-oxidation experiments on propene-NO_x-air and l-butene-NO_x-air mixtures were performed in the CSIRO indoor environmental chamber. These data were used to test the alkene sub-mechanisms from the Master Chemical Mechanism version 3.1 (MCM v3.1). A comparison of measured and modelled propene-NO_x data showed that the mechanisms required the inclusion of O(~3P) + parent alkene reactions in order to adequately model the results over a wide range of VOC/NO_x ratios. Sensitivity studies were performed on propene-NO_x and 1-butene-NO_x simulations to determine the effect of uncertainties in the chamber parameters and key photolysis rates on the O_3, and NO_x profiles. The low VOC/NO_x propene simulations were sensitive to the formaldehyde (HCHO) photolysis channel that produces HO_2 radicals and to the presence of O(~P) reactions. For the higher VOC/NO_x propene simulations, the O_3, and NO_x results were more sensitive to small changes in the initial HONO and NO_2 concentrations.