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

Abstract. The Master Chemical Mechanism has been updated from MCMv3 to MCMv3.1 in order to take into account recent improvements in the understanding of aromatic photo-oxidation. Newly available kinetic and product data from the literature have been incorporated into the mechanism. In particular, the degradation mechanisms for hydroxyarenes have been revised following the observation of high yields of ring-retained products, and product studies of aromatic oxidation under relatively low NOx conditions have provided new information on the branching ratios to first generation products. Experiments have been carried out at the European Photoreactor (EUPHORE) to investigate key subsets of the toluene system. These results have been used to test our understanding of toluene oxidation, and, where possible, refine the degradation mechanisms. The evaluation of MCMv3 and MCMv3.1 using data on benzene, toluene, p-xylene and 1,3,5-trimethylbenzene photosmog systems is described in a companion paper, and significant model shortcomings are identified. Ideas for additional modifications to the mechanisms, and for future experiments to further our knowledge of the details of aromatic photo-oxidation are discussed.

[1]  S. M. Aschmann,et al.  Products of the gas-phase reactions of o-,m- and p-xylene with the OH radical in thepresence and absence ofNOx , 1997 .

[2]  M. Jenkin,et al.  Evaluation of detailed aromatic mechanisms (MCMv3 and MCMv3.1) against environmental chamber data , 2004 .

[3]  Urs Baltensperger,et al.  Significance of semivolatile diesel exhaust organics for secondary HONO formation. , 2002, Environmental science & technology.

[4]  T. Kleindienst,et al.  Primary Product Distribution from the Reaction of Hydroxyl Radicals with Toluene at ppb NOX Mixing Ratios , 1998 .

[5]  Takashi Imamura,et al.  OH-initiated oxidation of benzene Part I . Phenol formation under atmospheric conditions , 2002 .

[6]  R. Olariu.  Atmospheric Oxidation of Selected Aromatic Hydrocarbons , 2002 .

[7]  R. Derwent,et al.  Atmospheric Chemistry and Physics Protocol for the Development of the Master Chemical Mechanism, Mcm V3 (part B): Tropospheric Degradation of Aromatic Volatile Organic Compounds , 2022 .

[8]  R. Derwent,et al.  Photochemical ozone creation potentials for a large number of reactive hydrocarbons under European conditions , 1996 .

[9]  R. Volkamer.  A DOAS Study on the Oxidation Mechanism of Aromatic Hydrocarbons under Simulated Atmospheric Conditions , 2001 .

[10]  I. Barnes,et al.  Rate coefficients for the gas-phase reaction of OH radicals with selected dihydroxybenzenes and benzoquinones , 2000 .

[11]  I. Barnes,et al.  Atmospheric Chemistry of Unsaturated Carbonyls: Butenedial, 4-Oxo-2-pentenal, 3-Hexene-2,5-dione, Maleic Anhydride, 3H-Furan-2-one, and 5-Methyl-3H-furan-2-one. , 1994, Environmental science & technology.

[12]  I. Barnes,et al.  FT–IR study of the ring-retaining products from the reaction of OH radicals with phenol, o-, m-, and p-cresol , 2002 .

[13]  Jack G. Calvert,et al.  The mechanisms of atmospheric oxidation of aromatic hydrocarbons , 2002 .

[14]  J. Arey,et al.  Products of the OH radical-initiated reaction of 3-hexene-2,5-dione. , 2001, Environmental science & technology.

[15]  A. Lewis,et al.  Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography , 2003 .

[16]  P. Wiesen,et al.  Heterogeneous conversion of NO 2 on secondary organic aerosol surfaces: A possible source of nitrous acid (HONO) in the atmosphere? , 2003 .

[17]  S. M. Aschmann,et al.  Formation and atmospheric reactions of 4,5-dihydro-2-methylfuran , 2002 .

[18]  J. Yu,et al.  Atmospheric photooxidation of alkylbenzenes—II. Evidence of formation of epoxide intermediates , 1997 .

[19]  U. Baltensperger,et al.  Heterogeneous reaction of NO2 on diesel soot particles. , 2001, Environmental science & technology.

[20]  L. Bartolotti,et al.  Density functional theory derived intermediates from the OH initiated atmospheric oxidation of toluene , 1995 .

[21]  U. Baltensperger,et al.  Identification of Polymers as Major Components of Atmospheric Organic Aerosols , 2004, Science.

[22]  Michael J. Pilling,et al.  Validation of the calibration of a laser-induced fluorescence instrument for the measurement of OH radicals in the atmosphere , 2003 .

[23]  E. Grosjean,et al.  The Reaction of Unsaturated Aliphatic Oxygenates with Ozone , 1999 .

[24]  S. M. Aschmann,et al.  Products of the Gas-Phase Reactions of Aromatic Hydrocarbons: Effect of NO2 Concentration. , 1995 .

[25]  M. Jenkin,et al.  Modelling of the photooxidation of toluene: conceptual ideas for validating detailed mechanisms , 2002 .

[26]  Ulrich Platt,et al.  Primary and Secondary Glyoxal Formation from Aromatics: Experimental Evidence for the Bicycloalkyl−Radical Pathway from Benzene, Toluene, and p-Xylene , 2001 .