Secondary aerosol formation from the oxidation of toluene by chlorine atoms

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• 作者：Xuyi Cai ; Luke D. Ziemba ; Robert J. Griffin
• 关键词：Chamber studies ; Chlorine atom ; Modeling studies ; Secondary organic aerosol ; Toluene
• 刊名：Atmospheric Environment
• 出版年：2008
• 出版时间：October 2008
• 年：2008
• 卷：42
• 期：32
• 页码：7348-7359
• 全文大小：616 K

文摘

Oxidation of toluene by chlorine atoms (Cl) was studied in a chamber. Secondary organic aerosol (SOA) yields ranged from 3.0 to 7.9 % for aerosol concentrations up to 12.0 μg m⁻³. SOA yields from toluene/Cl reactions and model parameters related to aerosol growth depend on the initial ratio of molecular chlorine to toluene. Data from an Aerodyne quadrupole Aerosol Mass Spectrometer (Q-AMS) indicate that a small fraction of the generated aerosol mass is inorganic chloride (approximately 4 % ), that inorganic chloride aerosol growth ceases contemporaneously with that of SOA, and that particles are mixed internally. Analysis of Q-AMS spectra indicates predominance of species that traditionally are thought to be representative of SOA but with increased importance of aromatic/ring-retaining products. Mechanistic modeling of the toluene system indicates that final SOA products likely result from the oxidation of quinone type compounds derived via oxidation of the first-generation product benzaldehyde. Zero-dimensional calculations indicate Cl-initiated oxidation could be as important as hydroxyl-radical-initiated oxidation in SOA formation from toluene in early morning in certain coastal or industrialized areas.