Secondary Organic Aerosol from Oxygenated Precursors: Mass Yields, Composition, and Parameters for Chemical Transport Models

SHANTANU JATHAR, Abraham Dearden, Allison Piasecki, Ann M. Middlebrook, Katelyn Rediger, Matthew Coggon, Cort Zang, Tucker Melles, Megan Willis, Chelsea Stockwell, Lu Xu, Carsten Warneke, Rebecca Schwantes, Brian McDonald, Christopher Cappa, Delphine K. Farmer, Colorado State University

     Abstract Number: 358
     Working Group: Aerosol Sources and Constituents of Emerging Importance and Their Impacts across Spatial Scales

Abstract
Volatile chemical products (VCPs) consist of hydrocarbons (HCs) and oxygenated volatile organic compounds (OVOCs), both of can oxidize in the atmosphere to form secondary organic aerosol (SOA). While the SOA contribution from VCP HCs can be estimated from historical data on alkanes, alkenes, and aromatics, there are few laboratory studies that can be used to inform SOA production from VCP OVOCs. This has meant that the contribution of VCP OVOCs to anthropogenic SOA has remained uncertain. In this work, we performed a set of experiments in a 10 m³ environmental chamber at Colorado State University to study the oxidation chemistry of VCP OVOCs leading to SOA formation. We performed a total of sixteen chamber experiments on eleven different VCP OVOCs - representing a diversity of compound classes - under moist (relative humidity ~ 55%) and moderate NO_X (30 ppbv) conditions. Gases and vapors were characterized using mass spectrometers while particles were measured using mass spectrometry and sizing, counting, and filter-based instruments. The findings outlined below are preliminary. Consistent with previous work, benzyl alcohol, carbitol, and butyl carbitol exhibited rapid and large SOA production with mass yields that exceeded 30% and texanol, D4 siloxane, butyl acetate, and dipropylene glycol formed little to no SOA. Surprisingly, dipropylene glycol methyl ether and dipropylene glycol butyl ether were not as efficient in forming SOA compared to glycol ethers like carbitol and butyl carbitol. Furfural oxidation resulted in high SOA mass yields (20%), with evidence that approximately half of the SOA was formed via aqueous pathways. Ongoing work is focused on (i) understanding the influence of the carbon and oxygen numbers and functional moieties on SOA mass yields and O:C ratios and (ii) development of volatility basis set-based parameters for use in chemical transport models.