Protocol for the development of the Master Chemical Mechanism, MCM v3 (Part B): tropospheric degradation of aromatic volatile organic compounds

[摘要] Kinetic and mechanistic data relevant to the tropospheric degradation of aromatic volatileorganic compounds (VOC) have been used to define a mechanism development protocol,which has been used to construct degradation schemes for 18 aromatic VOC as part of version 3of the Master Chemical Mechanism (MCM v3). This is complementary to the treatment of 107non-aromatic VOC, presented in a companion paper. The protocol is divided into a series ofsubsections describing initiation reactions, the degradation chemistry to first generation productsvia a number of competitive routes, and the further degradation of first and subsequentgeneration products. Emphasis is placed on describing where the treatment differs from thatapplied to the non-aromatic VOC. The protocol is based on work available in the open literatureup to the beginning of 2001, and some other studies known by the authors which were underreview at the time.Photochemical Ozone Creation Potentials (POCP) have been calculated forthe 18 aromatic VOC in MCM v3 for idealised conditions appropriate to north-west Europe,using a photochemical trajectory model. The POCP values provide a measure of the relativeozone forming abilities of the VOC. These show distinct differences from POCP valuescalculated previously for the aromatics, using earlier versions of the MCM, and reasons forthese differences are discussed.

[学科分类] 大气科学