Particle Phase Acidity and Oligomer Formation in Secondary Organic Aerosol
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- 作者：Song Gao ; Nga L. Ng ; Melita Keywood ; Varuntida Varutbangkul ; Roya Bahreini ; Athanasios Nenes ; Jiwen He ; Kee Y. Yoo ; J. L. Beauchamp ; Robert P. Hodyss ; Richard C. Flagan ; and John H. Seinfeld
- 刊名：Environmental Science & Technology
- 出版年：2004
- 出版时间：December 15, 2004
- 年：2004
- 卷：38
- 期：24
- 页码：6582 - 6589
- 全文大小：638K
- 年卷期：v.38,no.24(December 15, 2004)
- ISSN：1520-5851
文摘
A series of controlled laboratory experiments are carriedout in dual Teflon chambers to examine the presence ofoligomers in secondary organic aerosols (SOA) fromhydrocarbon ozonolysis as well as to explore the effect ofparticle phase acidity on SOA formation. In all sevenhydrocarbon systems studied (i.e., 
-pinene, cyclohexene,1-methyl cyclopentene, cycloheptene, 1-methyl cyclohexene,cyclooctene, and terpinolene), oligomers with MW from 250to 1600 are present in the SOA formed, both in theabsence and presence of seed particles and regardlessof the seed particle acidity. These oligomers are comparableto, and in some cases, exceed the low molecular weightspecies (MW < 250) in ion intensities in the ion trap massspectra, suggesting they may comprise a substantialfraction of the total aerosol mass. It is possible that oligomersare widely present in atmospheric organic aerosols,formed through acid- or base-catalyzed heterogeneousreactions. In addition, as the seed particle acidity increases,larger oligomers are formed more abundantly in theSOA; consequently, the overall SOA yield also increases.This explicit effect of particle phase acidity on the compositionand yield of SOA may have important climatic consequencesand need to be considered in relevant models.
-pinene, cyclohexene,1-methyl cyclopentene, cycloheptene, 1-methyl cyclohexene,cyclooctene, and terpinolene), oligomers with MW from 250to 1600 are present in the SOA formed, both in theabsence and presence of seed particles and regardlessof the seed particle acidity. These oligomers are comparableto, and in some cases, exceed the low molecular weightspecies (MW < 250) in ion intensities in the ion trap massspectra, suggesting they may comprise a substantialfraction of the total aerosol mass. It is possible that oligomersare widely present in atmospheric organic aerosols,formed through acid- or base-catalyzed heterogeneousreactions. In addition, as the seed particle acidity increases,larger oligomers are formed more abundantly in theSOA; consequently, the overall SOA yield also increases.This explicit effect of particle phase acidity on the compositionand yield of SOA may have important climatic consequencesand need to be considered in relevant models.