AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Effect of Aerosol Water on Chemical Composition and Aging of Organic Aerosols
SERGEY NIZKORODOV, Mallory Hinks, Julia Montoya, Lucas Ellison, Kurtis Malecha, Paige Aiona, Manabu Shiraiwa, Donald Dabdub, Peng Lin, Alexander Laskin, Julia Laskin, University of California, Irvine
Abstract Number: 396 Working Group: There Must be Something in the Water: Cloud, Fog and Aerosol Aqueous Chemistry for Aerosol Production
Abstract This presentation will discuss multiple effects water vapor and aerosol liquid water can have on chemical composition of organic particles: (a) gaseous water can directly participate in the VOC oxidation reactions, such as carbonyl oxides; (b) aerosol liquid water present in hygroscopic particles can lead to hydrolysis of organic compounds and other particle-phase reactions involving or catalyzed by water; (c) aerosol liquid water has a strong effect on acidity of particles and, therefore, affects acid-catalyzed processes occurring in particles; (d) water can act as a plasticizer for SOA particles making them less viscous, thus affecting the rate of their growth and chemical aging; (e) under supersaturated conditions, aqueous chemistry occurring in cloud and fog droplets promotes photolysis driven conversion of small water-soluble molecules into non-volatile products that would not form in the absence of liquid water, as well as photodegradation of dissolved SOA compounds. These effects will be exemplified with several recent studies, including the effect of relative humidity on the yield and chemical composition of SOA formed from toluene, hydrolysis of SOA compounds in aerosol water, and photochemistry of SOA at different levels of relative humidity.