High-Molecular Weight Dimer Esters Are Major Products in Aerosols from α-Pinene Ozonolysis and the Boreal Forest

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• 作者：Kasper Kristensen ; Ågot K. Watne ; Julia Hammes ; Anna Lutz ; Tuukka Petäjä ; Mattias Hallquist ; Merete Bilde ; Marianne Glasius
• 刊名：Environmental Science & Technology Letters
• 出版年：2016
• 出版时间：August 9, 2016
• 年：2016
• 卷：3
• 期：8
• 页码：280-285
• 全文大小：536K
• 年卷期：0

文摘

This study investigates the contribution of high-molecular weight dimer esters to laboratory-generated α-pinene gas- and particle-phase secondary organic aerosol (SOA) and particulate matter (PM) collected at the Nordic boreal forest site of Hyytiälä, Finland. Laboratory flow reactor experiments (25 °C) show that dimer esters from ozonolysis of α-pinene contribute between 5 and 16% of the freshly formed α-pinene particle-phase SOA mass. An increased level of formation is observed at a higher relative humidity of ∼40%, and the presence of a hydroxyl radical (OH) scavenger is shown to affect the formation of dimer esters. Of the 28 dimer esters identified in laboratory α-pinene SOA, 15 are also observed in ambient PM samples, contributing between 0.5 and 1.6% of the total PM₁. The observed esters show good correlation with known α-pinene SOA tracers in collected PM samples. This work reveals an, until now, unrecognized contribution of dimer esters from α-pinene oxidation to boreal forest PM.