Evidence for organosulfates in secondary organic aerosol.
Recent work has shown that particle-phase reactions contribute to the formation of secondary organic aerosol (SOA), with enhancements of SOA yields in the presence of acidic seed aerosol. In this study, the chemical composition of SOA from the photooxidations of alpha-pinene and isoprene, in the presence or absence of sulfate seed aerosol, is investigated through a series of controlled chamber experiments in two separate laboratories. By using electrospray ionization-mass spectrometry, sulfate esters in SOA produced in laboratory photooxidation experiments are identified for the first time. Sulfate esters are found to account for a larger fraction of the SOA mass when the acidity of seed aerosol is increased, a result consistent with aerosol acidity increasing SOA formation. Many of the isoprene and alpha-pinene sulfate esters identified in these chamber experiments are also found in ambient aerosol collected at several locations in the southeastern U.S. It is likely that this pathway is important for other biogenic terpenes, and may be important in the formation of humic-like substances (HULIS) in ambient aerosol.
Surratt
Jason D
JD
Department of Chemistry, California Institute of Technology, Pasadena, California 91125, USA.
Kroll
Jesse H
JH
Kleindienst
Tadeusz E
TE
Edney
Edward O
EO
Claeys
Magda
M
Sorooshian
Armin
A
Ng
Nga L
NL
Offenberg
John H
JH
Lewandowski
Michael
M
Jaoui
Mohammed
M
Flagan
Richard C
RC
Seinfeld
John H
JH
D000336:Aerosols / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D000081008:Bicyclic Monoterpenes; D002070:Butadienes / Q000737:chemistry; D045782:Hemiterpenes / Q000737:chemistry; D013058:Mass Spectrometry; D015394:Molecular Structure; D039821:Monoterpenes / Q000737:chemistry; D010084:Oxidation-Reduction; D010420:Pentanes / Q000737:chemistry; D010777:Photochemistry; D013463:Sulfuric Acid Esters / Q000032:analysis* / Q000737:chemistry
D000336:Aerosols; D000393:Air Pollutants; D000081008:Bicyclic Monoterpenes; D002070:Butadienes; D045782:Hemiterpenes; D039821:Monoterpenes; D010420:Pentanes; D013463:Sulfuric Acid Esters; C005059:isoprene; C005451:alpha-pinene