Insights into Secondary Organic Aerosol Formation Mechanisms from Measured Gas/Particle Partitioning of Specific Organic Tracer Compounds

TitleInsights into Secondary Organic Aerosol Formation Mechanisms from Measured Gas/Particle Partitioning of Specific Organic Tracer Compounds
Publication TypeJournal Article
Year of Publication2013
AuthorsZhao YL, Kreisberg NM, Worton DR, Isaacman G, Weber RJ, Liu S, Day DA, Russell LM, Markovic MZ, VandenBoer TC, Murphy JG, Hering SV, Goldstein AH
JournalEnvironmental Science & Technology
Volume47
Pagination3781-3787
Date Published2013/04
Type of ArticleArticle
ISBN Number0013-936X
Accession NumberWOS:000317813400031
Keywordsacidity; alpha-pinene; atmosphere; california; constituents; humidity; kinetics; ozonolysis; pm2.5; source apportionment
Abstract

In situ measurements of organic compounds in both gas and particle phases were made with a thermal desorption aerosol gas chromatography (TAG) instrument. The gas/particle partitioning of phthalic acid, pinonaldehyde, and 6,10,14-trimethyl-2-pentadecanone is discussed in detail to explore secondary organic aerosol (SOA) formation mechanisms. Measured fractions in the particle phase (f(part)) of 6,10,14-trimethyl-2-pentadecanone were similar to those expected from the absorptive gas/particle partitioning theory, suggesting that its partitioning is dominated by absorption processes. However, f(part), of phthalic acid and pinonaldehyde were substantially higher than predicted. The formation of low-volatility products from reactions of phthalic acid with ammonia is proposed as one possible mechanism to explain the high f(part) of phthalic acid. The observations of particle-phase pinonaldehyde when inorganic acids were fully neutralized indicate that inorganic acids are not required for the occurrence of reactive uptake of pinonaldehyde on particles. The observed relationship between f(part) of pinonaldehyde and relative humidity suggests that the aerosol water plays a significant role in the formation of particle-phase pinonaldehyde. Our results clearly show it is necessary to include multiple gas/particle partitioning pathways in models to predict SOA and multiple SOA tracers in source apportionment models to reconstruct SOA.

DOI10.1021/es304587x
Short TitleEnviron. Sci. Technol.
Integrated Research Themes: