Chemical transformation of α-pinene-derived organosulfate via heterogeneous OH oxidation: implications for sources and environmental fates of atmospheric organosulfates.

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From: Atmospheric Chemistry and Physics(Vol. 22, Issue 8)
Publisher: Copernicus GmbH
Document Type: Brief article
Length: 382 words

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Abstract :

Organosulfur compounds are found to be ubiquitous in atmospheric aerosols - a majority of which are expected to be organosulfates (OSs). Given the atmospheric abundance of OSs, and their potential to form a variety of reaction products upon aging, it is imperative to study the transformation kinetics and chemistry of OSs to better elucidate their atmospheric fates and impacts. In this work, we investigated the chemical transformation of an α-pinene-derived organosulfate (C.sub.10 H.sub.17 O.sub.5 SNa, αpOS-249) through heterogeneous OH oxidation at a relative humidity of 50 % in an oxidation flow reactor (OFR). The aerosol-phase reaction products were characterized using high-performance liquid chromatography-electrospray ionization-high-resolution mass spectrometry and ion chromatography. By monitoring the decay rates of αpOS-249, the effective heterogeneous OH reaction rate was measured to be (6.72±0.55)x10-13 cm.sup.3 molecule.sup.-1 s.sup.-1 . This infers an atmospheric lifetime of about 2 weeks at an average OH concentration of 1.5x10.sup.6 molecules cm.sup.-3 . Product analysis shows that OH oxidation of αpOS-249 can yield more oxygenated OSs with a nominal mass-to-charge ratio (m/z) at 247 (C.sub.10 H.sub.15 O.sub.5 S.sup.- ), 263 (C.sub.10 H.sub.15 O.sub.6 S.sup.- ), 265 (C.sub.10 H.sub.17 O.sub.6 S.sup.- ), 277 (C.sub.10 H.sub.13 O.sub.7 S.sup.- ), 279 (C.sub.10 H.sub.15 O.sub.7 S.sup.- ), and 281 (C.sub.10 H.sub.17 O.sub.7 S.sup.-). The formation of fragmentation products, including both small OSs (C

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Gale Document Number: GALE|A702016276