Formation of Aqueous SOA from Water-Soluble Gaseous ɑ-Pinene Oxidation Products and from Gases Emitted by Biomass Burning Emissions

MATT ZARAGOZA, Sergey Nizkorodov, Annmarie Carlton, University of California, Irvine

     Abstract Number: 648
     Working Group: Carbonaceous Aerosols

Abstract
Aqueous secondary organic aerosol (aqSOA) refers to compounds that are produced by aqueous oxidation of small organic molecules in cloud and fog water. A number of experiments on the formation of aqSOA from individual compounds (such as phenols, glyoxal, methyl glyoxal, pyruvic acid, etc.) have been done in the past. However, aqueous droplets contain complex mixtures of water-soluble organic gases, and it is important to study aqSOA formation from environmentally relevant mixtures. The goal of this work is to study the formation of aqSOA from water-soluble gaseous ɑ-pinene oxidation products and from gases emitted by biomass burning emissions. Gaseous ɑ-pinene oxidation products were generated in an oxidation flow reactor using OH as the primary oxidant. Ozone was photolyzed in the presence of water vapor to produce OH radicals, which initiated the oxidation of ɑ-pinene. The oxidation products were passed through a Teflon 0.2 um filter to remove particulate compounds. A mist chamber was used to scrub the remaining gaseous products into an aqueous solution to separate water-soluble components from insoluble components. Photooxidation experiments were then performed by adding hydrogen peroxide to the solution and exposing the solution to 254 nm radiation to simulate secondary cloud-processing across various time intervals. Mass spectrometry was used to observe products of aqueous photooxidation. The volatility of the observed products was predicted from their molecular formulas to assess whether these products have low enough volatility to contribute to aqSOA. The experiments are currently ongoing, and the first results should be available by the time of the AAAR meeting.