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ß-CARYOPHYLLINIC ACID: AN ATMOSPHERIC TRACER FOR ß-CARYOPHYLLENE SECONDARY ORGANIC AEROSOL
Citation:
JAOUI, M., M. LEWANDOWSKI, T. E. KLEINDIENST, J. H. OFFENBERG, AND E. O. EDNEY. ß-CARYOPHYLLINIC ACID: AN ATMOSPHERIC TRACER FOR ß-CARYOPHYLLENE SECONDARY ORGANIC AEROSOL. GEOPHYSICAL RESEARCH LETTERS. American Geophysical Union, Washington, DC, 34(5):L05816 1-4, (2007).
Impact/Purpose:
PM Chemistry models for predicting chemical compositions of PM2.5 are needed to assess PM2.5 control strategies. Because of the chemical complexity of ambient PM2.5, models must be developed to predict ambient concentrations of water, inorganics, and organics in the aerosols. Under this research task, the current treatments of secondary organic aerosol formation and the chemistry of N2O5 in CMAQ will be improved by HEASD and integrated into CMAQ by AMD. CMAQ will be used by AMD to predict ambient concentrations and compositions of PM2.5 for OAQPS.
Description:
The chemical compositions of ambient PM2.5 samples, collected in Research Triangle Park, North Carolina, USA, and a sample of secondary organic aerosol, formed by irradiating a mixture of the sesquiterpene, ß-caryophyllene, and oxides of nitrogen in a smog chamber, were chemically analyzed using derivative-based GC-MS methods. The analyses showed the presence of an oxidized compound, tentatively identified as ß-caryophyllinic acid, in both the ambient PM2.5 field samples and in the smog chamber sample. The seasonal concentrations of ß-caryophyllinic acid in the ambient PM2.5 samples were 0.5, 0.9, 7.0, and 0.5 ng m-3 during the winter, spring, summer and fall respectively. To our knowledge, this is the first time that an oxidation product of a sesquiterpene, a hydrocarbon with high secondary organic aerosol yields and emitted from plants and trees in significant quantities, has been detected in ambient PM2.5 samples.