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Secondary Organic Aerosol Yields from the Oxidation of Benzyl Alcohol
SOPHIA CHARAN, Reina Buenconsejo, John Seinfeld, California Institute of Technology
Abstract Number: 228
Working Group: Missing contributors to SOA: The Role of Volatile Chemical Products (VCPS)
Abstract
Benzyl alcohol is a widely used compound in consumer products that can be found in soaps, inks, paints, and, consequently, indoor and outdoor air. Experimental and computationally simulated environmental data from chamber experiments of benzyl alcohol and OH provide an understanding of aerosol yield and chemistry under relevant urban conditions (5–200 ppb NO and 291–312 K) and give insight into the effect of volatile chemical products on the production of secondary organic aerosol (SOA). This research especially considers the physicochemical processes occurring in environmental chambers; in particular, the loss of particles and vapors to the chamber walls is accounted for. Analysis of the measured yield as a function of initial seed surface area concentration shows a clear seed surface area effect. Benzyl alcohol is found to have a large SOA formation potential; at NO concentrations of ~80 ppb and 291 K, SOA mass yields for benzyl alcohol can reach 1. This is much larger than previously predicted. Time-resolved SOA yields are presented as a function of temperature and NOx concentration. The SOA yield decreases with rising temperatures, and the aerosol formed at lower temperatures is more oxygenated and may contain fewer organonitrates. As the NO mixing ratio increases, the SOA yield decreases due to differing aerosol formation pathways. This study of benzyl alcohol indicates that SOA yields for similar volatile chemical products could be even larger than previously predicted.