Effective Henry鈥檚 Law Partitioning and the Salting Constant of Glyoxal in Aerosols Containing Sulfate

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• 作者：Christopher J. Kampf ; Eleanor M. Waxman ; Jay G. Slowik ; Josef Dommen ; Lisa Pfaffenberger ; Arnaud P. Praplan ; Andr茅 S. H. Pr茅v么t ; Urs Baltensperger ; Thorsten Hoffmann ; Rainer Volkamer
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：May 7, 2013
• 年：2013
• 卷：47
• 期：9
• 页码：4236-4244
• 全文大小：383K
• 年卷期：v.47,no.9(May 7, 2013)
• ISSN：1520-5851

文摘

The reversible partitioning of glyoxal was studied in simulation chamber experiments for the first time by time-resolved measurements of gas-phase and particle-phase concentrations in sulfate-containing aerosols. Two complementary methods for the measurement of glyoxal particle-phase concentrations are compared: (1) an offline method utilizing filter sampling of chamber aerosols followed by HPLC-MS/MS analysis and (2) positive matrix factorization (PMF) analysis of aerosol mass spectrometer (AMS) data. Ammonium sulfate (AS) and internally mixed ammonium sulfate/fulvic acid (AS/FA) seed aerosols both show an exponential increase of effective Henry鈥檚 law coefficients (K_H,eff) with AS concentration (c_AS, in mol kg^鈥? aerosol liquid water, m = molality) and sulfate ionic strength, I(SO₄^{2鈥?/sup>) (m). A modified Setschenow plot confirmed that 鈥渟alting-in鈥?of glyoxal is responsible for the increased partitioning. The salting constant for glyoxal in AS is KS_CHOCHO = (鈭?.24 卤 0.02) m鈥?, and found to be independent of the presence of FA. The reversible glyoxal uptake can be described by two distinct reservoirs for monomers and higher molecular weight species filling up at characteristic time constants. These time constants are 蟿₁ 鈮?102 s and 蟿₂ 鈮?104 s at c_AS < 12 m, and about 1鈥? orders of magnitude slower at higher c_AS, suggesting that glyoxal uptake is kinetically limited at high salt concentrations.}