title: Organic aerosol formation during the atmospheric degradation of toluene.
abstract: Organic aerosol formation during the atmospheric oxidation of toluene was investigated using smog chamber systems. Toluene oxidation was initiated by the UV irradiation of either toluene/air/NOx or toluene/air/CH3ONO/NO mixtures. Aerosol formation was monitored using scanning mobility particle sizers and toluene loss was monitored by in-situ FTIR spectroscopy or GC-FID techniques. The experimental results show that the reaction of OH radicals, NO3 radicals and/or ozone with the first generation products of toluene oxidation are sources of organic aerosol during the atmospheric oxidation of toluene. The aerosol results fall into two groups, aerosol formed in the absence and presence of ozone. An analytical expression for aerosol formation is developed and values are obtained for the yield of the aerosol species. In the absence of ozone the aerosol yield, defined as aerosol formed per unit toluene consumed once a threshold for aerosol formation has been exceeded, is 0.075 +/- 0.004. In the presence of ozone the aerosol yield is 0.108 +/- 0.004. This work provides experimental evidence and a simple theory confirming the formation of aerosol from secondary reactions.
authors.affiliation: Ford Motor Company, Dearborn, Michigan 48121-2053, USA. mhurley3@ford.com
authors.forename: M D
authors.initials: MD
authors.lastname: Hurley
authors.forename: O
authors.initials: O
authors.lastname: Sokolov
authors.forename: T J
authors.initials: TJ
authors.lastname: Wallington
authors.forename: H
authors.initials: H
authors.lastname: Takekawa
authors.forename: M
authors.initials: M
authors.lastname: Karasawa
authors.forename: B
authors.initials: B
authors.lastname: Klotz
authors.forename: I
authors.initials: I
authors.lastname: Barnes
authors.forename: K H
authors.initials: KH
authors.lastname: Becker
mesh_terms: D000336:Aerosols; D000393:Air Pollutants / Q000737:chemistry*; D009930:Organic Chemicals; D010083:Oxidants, Photochemical / Q000737:chemistry; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry; D014050:Toluene / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D009930:Organic Chemicals; D010083:Oxidants, Photochemical; D014050:Toluene; D010126:Ozone