| Title: | Characterization of Highly Oxidized Molecules in Fresh and Aged Biogenic Secondary Organic Aerosol |
| Author(s): | Tu P; Hall WA; Johnston MV; |
| Address: | "Department of Chemistry and Biochemistry, University of Delaware , Newark, Delaware 19716, United States. DFA of California , 1855 South Van Ness Avenue, Fresno, California 93721, United States" |
| DOI: | 10.1021/acs.analchem.6b00378 |
| ISSN/ISBN: | 1520-6882 (Electronic) 0003-2700 (Print) 0003-2700 (Linking) |
| Abstract: | "In this work, highly oxidized multifunctional molecules (HOMs) in fresh and aged secondary organic aerosol (SOA) derived from biogenic precursors are characterized with high-resolution mass spectrometry. Fresh SOA was generated by mixing ozone with a biogenic precursor (beta-pinene, limonene, alpha-pinene) in a flow tube reactor. Aging was performed by passing the fresh SOA through a photochemical reactor where it reacted with hydroxyl radicals. Although these aerosols were as a whole not highly oxidized, molecular analysis identified a significant number of HOMs embedded within it. HOMs in fresh SOA consisted mostly of monomers and dimers, which is consistent with condensation of extremely low-volatility organic compounds (ELVOCs) that have been detected in the gas phase in previous studies and linked to SOA particle formation. Aging caused an increase in the average number of carbon atoms per molecule of the HOMs, which is consistent with particle phase oxidation of (less oxidized) oligomers already existing in fresh SOA. HOMs having different combinations of oxygen-to-carbon ratio, hydrogen-to-carbon ratio and average carbon oxidation state are discussed and compared to low volatility oxygenated organic aerosol (LVOOA), which has been identified in ambient aerosol based on average elemental composition but not fully understood at a molecular level. For the biogenic precursors and experimental conditions studied, HOMs in fresh biogenic SOA have molecular formulas more closely resembling LVOOA than HOMs in aged SOA, suggesting that aging of biogenic SOA is not a good surrogate for ambient LVOOA" |
| Keywords: | Aerosols/chemistry Bicyclic Monoterpenes Bridged Bicyclo Compounds/*chemistry Cyclohexenes/*chemistry Limonene Mass Spectrometry Monoterpenes/*chemistry Oxidation-Reduction Ozone/*chemistry Terpenes/*chemistry; |
| Notes: | "MedlineTu, Peijun Hall, Wiley A 4th Johnston, Murray V eng P30 GM110758/GM/NIGMS NIH HHS/ S10 OD016267/OD/NIH HHS/ 1 P30 GM110758-01/GM/NIGMS NIH HHS/ S10 OD016267-01/OD/NIH HHS/ Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S. 2016/03/24 Anal Chem. 2016 Apr 19; 88(8):4495-501. doi: 10.1021/acs.analchem.6b00378. Epub 2016 Mar 29" |
