Modelling the evolution of organic carbon during its gas-phase tropospheric oxidation: development of an explicit model based on a self generating approach

[摘要] Organic compounds emitted in the atmosphere are oxidized in complex reactionsequences that produce a myriad of intermediates. Although the cumulativeimportance of these organic intermediates is widely acknowledged, there isstill a critical lack of information concerning the detailed composition ofthe highly functionalized secondary organics in the gas and condensed phases.The evaluation of their impacts on pollution episodes, climate, and thetropospheric oxidizing capacity requires modelling tools that track theidentity and reactivity of organic carbon in the various phases down to theultimate oxidation products, CO and CO₂. However, a fully detailedrepresentation of the atmospheric transformations of organic compoundsinvolves a very large number of intermediate species, far in excess of thenumber that can be reasonably written manually. This paper describes (1) thedevelopment of a data processing tool to generate the explicit gas-phaseoxidation schemes of acyclic hydrocarbons and their oxidation productsunder tropospheric conditions and (2)the protocol used to select the reaction products and the rate constants.Results are presented using the fully explicit oxidation schemes generatedfor two test species: n-heptane and isoprene. Comparisons withwell-established mechanisms were performed to evaluate these generatedschemes. Some preliminary results describing the gradual change of organiccarbon during the oxidation of a given parent compound are presented.

[学科分类] 大气科学