Aerosol speciation and mass prediction from toluene oxidation under high NOx conditions

作者:Kelly Janya L*; Michelangeli Diane V; Makar Paul A; Hastie Donald R; Mozurkewich Michael; Auld Janeen
来源:Atmospheric Environment, 2010, 44(3): 361-369.
DOI:10.1016/j.atmosenv.2009.10.035

摘要

A kinetically based gas-particle partitioning box model is used to highlight the importance of parameter representation in the prediction of secondary organic aerosol (SOA) formation following the photo-oxidation of toluene. The model is initialized using experimental data from York University's indoor smog chamber and provides a prediction of the total aerosol yield and speciation. A series of model sensitivity experiments were performed to study the aerosol speciation and mass prediction under high NOx conditions (VOC/NOx = 0.2). Sensitivity experiments indicate vapour pressure estimation to be a large area of weakness in predicting aerosol mass, creating an average total error range of 70 mu g m(-3) (range of 5-145 mu g m(-3)), using two different estimation methods. Aerosol speciation proved relatively insensitive to changes in vapour pressure. One species, 3-methyl-6-nitro-catechol, dominated the aerosol phase regardless of the vapour pressure parameterization used and comprised 73-88% of the aerosol by mass. The dominance is associated with the large concentration of 3-methyl-6-nitro-catechol in the gas-phase. The high NOx initial conditions of this study suggests that the predominance of 3-methyl-6-nitro-catechol likely results from the cresol-forming branch in the Master Chemical Mechanism taking a significant role in secondary organic aerosol formation under high NOx conditions. Further research into the yields and speciation leading to this reaction product is recommended.

  • 出版日期2010-1