Development of a detailed chemical mechanism (MCMv3.1) for the atmospheric oxidation of aromatic hydrocarbons

[摘要] The Master Chemical Mechanism has been updated from MCMv3 to MCMv3.1 inorder to take into account recent improvements in the understanding ofaromatic photo-oxidation. Newly available kinetic and product data from theliterature have been incorporated into the mechanism. In particular, thedegradation mechanisms for hydroxyarenes have been revised following theobservation of high yields of ring-retained products, and product studies ofaromatic oxidation under relatively low NO_x conditions have providednew information on the branching ratios to first generation products.Experiments have been carried out at the European Photoreactor (EUPHORE) toinvestigate key subsets of the toluene system. These results have been usedto test our understanding of toluene oxidation, and, where possible, refinethe degradation mechanisms. The evaluation of MCMv3 and MCMv3.1 using dataon benzene, toluene, p-xylene and 1,3,5-trimethylbenzene photosmog systems isdescribed in a companion paper, and significant model shortcomings areidentified. Ideas for additional modifications to the mechanisms, and forfuture experiments to further our knowledge of the details of aromaticphoto-oxidation are discussed.

[学科分类] 大气科学