Title: | Role of Aerosol Liquid Water in Secondary Organic Aerosol Formation from Volatile Organic Compounds |
Author(s): | Faust JA; Wong JP; Lee AK; Abbatt JP; |
Address: | "Department of Chemistry, University of Toronto , 80 Saint George Street, Toronto, Ontario M5S 3H6, Canada" |
ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
Abstract: | "A key mechanism for atmospheric secondary organic aerosol (SOA) formation occurs when oxidation products of volatile organic compounds condense onto pre-existing particles. Here, we examine effects of aerosol liquid water (ALW) on relative SOA yield and composition from alpha-pinene ozonolysis and the photooxidation of toluene and acetylene by OH. Reactions were conducted in a room-temperature flow tube under low-NO(x) conditions in the presence of equivalent loadings of deliquesced ( approximately 20 mug m(-3) ALW) or effloresced ( approximately 0.2 mug m(-3) ALW) ammonium sulfate seeds at exactly the same relative humidity (RH = 70%) and state of wall conditioning. We found 13% and 19% enhancements in relative SOA yield for the alpha-pinene and toluene systems, respectively, when seeds were deliquesced rather than effloresced. The relative yield doubled in the acetylene system, and this enhancement was partially reversible upon drying the prepared SOA, which reduced the yield by 40% within a time scale of seconds. We attribute the high relative yield of acetylene SOA on deliquesced seeds to aqueous partitioning and particle-phase reactions of the photooxidation product glyoxal. The observed range of relative yields for alpha-pinene, toluene, and acetylene SOA on deliquesced and effloresced seeds suggests that ALW plays a complicated, system-dependent role in SOA formation" |
Keywords: | Aerosols Air Pollutants Ammonium Sulfate Monoterpenes Oxidation-Reduction *Volatile Organic Compounds *Water; |
Notes: | "MedlineFaust, Jennifer A Wong, Jenny P S Lee, Alex K Y Abbatt, Jonathan P D eng Research Support, Non-U.S. Gov't 2017/01/27 Environ Sci Technol. 2017 Feb 7; 51(3):1405-1413. doi: 10.1021/acs.est.6b04700. Epub 2017 Jan 26" |