Document Detail

Secondary Organic Aerosol Formation from Low-NOx Photooxidation of Dodecane: Evolution of Multi-Generation Gas-Phase Chemistry and Aerosol Composition.
MedLine Citation:
PMID:  22424261     Owner:  NLM     Status:  Publisher    
The extended photooxidation of and secondary organic aerosol (SOA) formation from dodecane (C12H26) under low-NOx conditions, such that RO2 + HO2 chemistry dominates the fate of the peroxy radicals, is studied in the Caltech Environmental Chamber based on simultaneous gas and particle-phase measurements. A mechanism simulation indicates that greater than 67% of the initial carbon ends up as fourth and higher generation products after 10 h of reaction, and simulated trends for seven species are supported by gas-phase measurements. A characteristic set of hydroperoxide gas-phase products are formed under these low-NOx conditions. Production of semi-volatile hydroperoxide species within three generations of chemistry is consistent with observed initial aerosol growth. Continued gas-phase oxidation of these semivolatile species produces multi-functional low volatility compounds. This study elucidates the complex evolution of the gas-phase photooxidation chemistry and subsequent SOA formation through a novel approach comparing molecular level information from a chemical ionization mass spectrometer (CIMS) and high m/z ion fragments from an Aerodyne high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS). Combination of these techniques reveals that particle-phase chemistry leading to peroxyhemiacetal formation is the likely mechanism by which these species are incorporated in the particle phase. The current findings are relevant towards understanding atmospheric SOA formation and aging from the "unresolved complex mixture," comprising, in part, long-chain alkanes.
Lindsay D Yee; Jill S Craven; Christine L Loza; Katherine A Schilling; Nga Lee Ng; Manjula R Canagaratna; Paul Jeffrey Ziemann; Richard C Flagan; John H Seinfeld
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-3-16
Journal Detail:
Title:  The journal of physical chemistry. A     Volume:  -     ISSN:  1520-5215     ISO Abbreviation:  -     Publication Date:  2012 Mar 
Date Detail:
Created Date:  2012-3-19     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9890903     Medline TA:  J Phys Chem A     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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