Indoor SOA from OH Radical Chemistry Initiated by Chlorine
Pearl Abue, KATARINA KONON, Lea El Khoury, Mrinali Modi, Lea Hildebrandt Ruiz, University of Texas at Austin
Abstract Number: 467
Working Group: Indoor Aerosols
Abstract
Hydroxyl radical (OH) chemistry is a dominant source of secondary organic aerosol (SOA) in outdoor environments. Indoors, OH chemistry is thought to occur primarily when outdoor lighting penetrates indoors. Chlorine radical (Cl) chemistry can be initiated under indoor lighting, as chlorine gas (Cl2) and other Cl precursors can be photolyzed by LED and fluorescent lights. In the presence of NOx, Cl radical chemistry results in the formation of OH and resulting OH radical chemistry indoors. We conducted environmental chamber experiments on the Cl-initiated oxidation of limonene. We show based on data and chamber modeling results that, in the presence of NOx, concentrations of OH exceed concentrations of Cl by approximately one order of magnitude, and that most of the limonene is oxidized by OH, not Cl. Consistent with this, most observed gas and particle-phase products (including C10H17NO4 and C9H15NO5, for example) are from OH oxidation of limonene. Thus, OH chemistry can substantially influence indoor SOA loadings in the presence of chlorine (from e.g. cleaning) and NOx (from e.g. cooking).