Secondary organic aerosol formation from isoprene photooxidation.
Environ Sci Technol
; 40(6): 1869-77, 2006 Mar 15.
Article
em En
| MEDLINE
| ID: mdl-16570610
ABSTRACT
Recent work has shown that the atmospheric oxidation of isoprene (2-methyl-1,3-butadiene, C5H8) leads to the formation of secondary organic aerosol (SOA). In this study, the mechanism of SOA formation by isoprene photooxidation is comprehensively investigated, by measurements of SOA yields over a range of experimental conditions, namely isoprene and NOx concentrations. Hydrogen peroxide is used as the radical precursor, substantially constraining the observed gas-phase chemistry; all oxidation is dominated by the OH radical, and organic peroxy radicals (RO2) react only with HO2 (formed in the OH + H2O2 reaction) or NO concentrations, including NOx-free conditions. At high NOx, yields are found to decrease substantially with increasing [NOx], indicating the importance of RO2 chemistry in SOA formation. Under low-NOx conditions, SOA mass is observed to decay rapidly, a result of chemical reactions of semivolatile SOA components, most likely organic hydroperoxides.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Compostos Orgânicos
/
Pentanos
/
Butadienos
/
Aerossóis
/
Hemiterpenos
/
Poluentes Atmosféricos
Idioma:
En
Revista:
Environ Sci Technol
Ano de publicação:
2006
Tipo de documento:
Article
País de afiliação:
Estados Unidos