Organic Aerosol Formation: OH (Hydroxyl Radical) vs. Ozone Oxidation Pathways

摘要

Results of an investigation of oxidation pathways leading to organic aerosol formation from selected precursor compounds are reported. 1-hexene, 1,7-octadiene, cyclopentene, cyclohexene, toluene, meta-xylene, and 1,3,5-trimethylbenzene were investigated. The experimental program was conducted in the University of North Carolina outdoor aerosol chamber under three experimental protocols. Experimental conditions were selected to emphasize the role of ozone, hydroxyl radical, and a combination of ozone and hydroxyl radical attack on a single organic aerosol precursor compound. The ozone oxidation pathway experiments yielded information about the amounts of aerosol formed from alkenes and aromatics and kinetic information on four alkene compounds. For the four alkene compounds, with the exception of 1-hexene, the presence of ozone is important in forming hydrocarbon oxidation products with sufficiently low vapor pressures to form organic aerosols.