Organosulfate formation in biogenic secondary organic aerosol.
Organosulfates of isoprene, alpha-pinene, and beta-pinene have recently been identified in both laboratory-generated and ambient secondary organic aerosol (SOA). In this study, the mechanism and ubiquity of organosulfate formation in biogenic SOA is investigated by a comprehensive series of laboratory photooxidation (i.e., OH-initiated oxidation) and nighttime oxidation (i.e., NO3-initiated oxidation under dark conditions) experiments using nine monoterpenes (alpha-pinene, beta-pinene, d-limonene, l-limonene, alpha-terpinene, gamma-terpinene, terpinolene, Delta(3)-carene, and beta-phellandrene) and three monoterpenes (alpha-pinene, d-limonene, and l-limonene), respectively. Organosulfates were characterized using liquid chromatographic techniques coupled to electrospray ionization combined with both linear ion trap and high-resolution time-of-flight mass spectrometry. Organosulfates are formed only when monoterpenes are oxidized in the presence of acidified sulfate seed aerosol, a result consistent with prior work. Archived laboratory-generated isoprene SOA and ambient filter samples collected from the southeastern U.S. were reexamined for organosulfates. By comparing the tandem mass spectrometric and accurate mass measurements collected for both the laboratory-generated and ambient aerosol, previously uncharacterized ambient organic aerosol components are found to be organosulfates of isoprene, alpha-pinene, beta-pinene, and limonene-like monoterpenes (e.g., myrcene), demonstrating the ubiquity of organosulfate formation in ambient SOA. Several of the organosulfates of isoprene and of the monoterpenes characterized in this study are ambient tracer compounds for the occurrence of biogenic SOA formation under acidic conditions. Furthermore, the nighttime oxidation experiments conducted under highly acidic conditions reveal a viable mechanism for the formation of previously identified nitrooxy organosulfates found in ambient nighttime aerosol samples. We estimate that the organosulfate contribution to the total organic mass fraction of ambient aerosol collected from K-puszta, Hungary, a field site with a similar organosulfate composition as that found in the present study for the southeastern U.S., can be as high as 30%.
Surratt
Jason D
JD
Department of Chemistry, California Institute of Technology, Pasadena, California 91125, USA.
Gómez-González
Yadian
Y
Chan
Arthur W H
AW
Vermeylen
Reinhilde
R
Shahgholi
Mona
M
Kleindienst
Tadeusz E
TE
Edney
Edward O
EO
Offenberg
John H
JH
Lewandowski
Michael
M
Jaoui
Mohammed
M
Maenhaut
Willy
W
Claeys
Magda
M
Flagan
Richard C
RC
Seinfeld
John H
JH
D000080462:Acyclic Monoterpenes; D000336:Aerosols / Q000737:chemistry*; D000393:Air Pollutants / Q000737:chemistry*; D000475:Alkenes / Q000737:chemistry; D000081008:Bicyclic Monoterpenes; D001643:Bridged Bicyclo Compounds / Q000737:chemistry; D002070:Butadienes / Q000737:chemistry; D002853:Chromatography, Liquid; D053138:Cyclohexenes / Q000737:chemistry; D045782:Hemiterpenes / Q000737:chemistry; D000077222:Limonene; D013058:Mass Spectrometry; D039821:Monoterpenes / Q000737:chemistry; D010084:Oxidation-Reduction; D010420:Pentanes / Q000737:chemistry; D010777:Photochemistry; D013463:Sulfuric Acid Esters / Q000737:chemistry*; D013729:Terpenes / Q000737:chemistry; D014835:Volatilization
D000080462:Acyclic Monoterpenes; D000336:Aerosols; D000393:Air Pollutants; D000475:Alkenes; D000081008:Bicyclic Monoterpenes; D001643:Bridged Bicyclo Compounds; D002070:Butadienes; D053138:Cyclohexenes; D045782:Hemiterpenes; D039821:Monoterpenes; D010420:Pentanes; D013463:Sulfuric Acid Esters; D013729:Terpenes; C005059:isoprene; C509595:myrcene; C010789:beta-pinene; D000077222:Limonene; C005451:alpha-pinene