| Title: | Volatility of organic molecular markers used for source apportionment analysis: measurements and implications for atmospheric lifetime |
| Author(s): | May AA; Saleh R; Hennigan CJ; Donahue NM; Robinson AL; |
| Address: | "Center for Atmospheric Particle Studies, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, USA" |
| ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
| Abstract: | "Molecular markers are organic species used to define fingerprints for source apportionment of ambient fine particulate matter. Traditionally, these markers have been assumed to be stable in the atmosphere. This work investigates the gas-particle partitioning of eight organic species used as molecular markers in receptor models for biomass burning (levoglucosan), motor vehicles (5alpha-cholestane, n-hexacosane, n-triacontane, 1,2-benz[a]anthracene, coronene), and meat cooking (cholesterol, oleic acid). Experiments were conducted using a thermodenuder to measure the evaporation of single component particles. The data were analyzed using the integrated volume method to determine saturation concentrations and enthalpies of vaporization for each compound. The results indicate that appreciable quantities (>10%) of most of these markers exist in the gas phase under typical atmospheric conditions. Therefore, these species should be considered semivolatile. Predictions from a chemical kinetics model indicate that gas-particle partitioning has important effects on the atmospheric lifetime of these species. The atmospheric decay of semivolatile compounds proceeds much more rapidly than nonvolatile compounds because gas-phase oxidation induces evaporation of particle-phase material. Therefore, both gas-particle partitioning and chemical reactions need to be accounted for when semivolatile molecular markers are used for source apportionment studies" |
| Keywords: | "Air Pollutants/analysis/*chemistry Biomass Cooking Environmental Monitoring/*methods Fires Models, Theoretical Organic Chemicals/*analysis/*chemistry Particulate Matter/*analysis/*chemistry Thermodynamics Vehicle Emissions/analysis Volatilization;" |
| Notes: | "MedlineMay, Andrew A Saleh, Rawad Hennigan, Christopher J Donahue, Neil M Robinson, Allen L eng Evaluation Study Research Support, U.S. Gov't, Non-P.H.S. 2012/09/28 Environ Sci Technol. 2012 Nov 20; 46(22):12435-44. doi: 10.1021/es302276t. Epub 2012 Oct 29" |
