| Title: | Influence of ozone and radical chemistry on limonene organic aerosol production and thermal characteristics |
| Author(s): | Pathak RK; Salo K; Emanuelsson EU; Cai C; Lutz A; Hallquist AM; Hallquist M; |
| Address: | "Atmospheric Science, Department of Chemistry and Molecular Biology, University of Gothenburg, S-412 96 Gothenburg, Sweden" |
| ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
| Abstract: | "Limonene has a strong tendency to form secondary organic aerosol (SOA) in the atmosphere and in indoor environments. Initial oxidation occurs mainly via ozone or OH radical chemistry. We studied the effect of O(3) concentrations with or without a OH radical scavenger (2-butanol) on the SOA mass and thermal characteristics using the Gothenburg Flow Reactor for Oxidation Studies at Low Temperatures and a volatility tandem differential mobility analyzer. The SOA mass using 15 ppb limonene was strongly dependent on O(3) concentrations and the presence of a scavenger. The SOA volatility in the presence of a scavenger decreased with increasing levels of O(3), whereas without a scavenger, there was no significant change. A chemical kinetic model was developed to simulate the observations using vapor pressure estimates for compounds that potentially contributed to SOA. The model showed that the product distribution was affected by changes in both OH and ozone concentrations, which partly explained the observed changes in volatility, but was strongly dependent on accurate vapor pressure estimation methods. The model-experiment comparison indicated a need to consider organic peroxides as important SOA constituents. The experimental findings could be explained by secondary condensed-phase ozone chemistry, which competes with OH radicals for the oxidation of primary unsaturated products" |
| Keywords: | "Aerosols Butanols/*chemistry Computer Simulation Cyclohexenes/*chemistry Hydroxyl Radical/*chemistry Limonene Models, Chemical Oxidants/*chemistry Ozone/*chemistry Temperature Terpenes/*chemistry Volatilization Water/chemistry;" |
| Notes: | "MedlinePathak, Ravi K Salo, Kent Emanuelsson, Eva U Cai, Cilan Lutz, Anna Hallquist, Asa M Hallquist, Mattias eng Research Support, Non-U.S. Gov't 2012/09/19 Environ Sci Technol. 2012 Nov 6; 46(21):11660-9. doi: 10.1021/es301750r. Epub 2012 Oct 10" |
