title: Uptake of Semivolatile Secondary Organic Aerosol Formed from α-Pinene into Nonvolatile Polyethylene Glycol Probe Particles.
abstract: Semivolatile organic compounds (SVOCs) play an essential role in secondary organic aerosol (SOA) formation, chemical aging, and mixing of organic aerosol (OA) from different sources. Polyethylene glycol (PEG400) particles are liquid, polar, and nearly nonvolatile; they provide a new vehicle to study the interaction between SVOCs with OA. With a unique fragment ion C4H9O2(+) (m/z 89), PEG400 can be easily separated from α-pinene SOA in aerosol mass spectra. By injecting separately prepared PEG probe particles into a chamber containing SOA coated on ammonium sulfate seeds, we show that a substantial pool of SVOCs exists in equilibrium with the original SOA particles. Quantitative findings are based on bulk mass spectra, size-dependent composition, and the evolution of individual particle mass spectra, which we use to separate the two particle populations. We observed a larger fraction of SVOC vapors with increased amounts of reacted α-pinene. For the same amount of reacted α-pinene, the SOA formed from α-pinene oxidized by OH radicals had a higher fraction of SOA vapors than SOA formed by α-pinene ozonolysis. Compared to the PEG400 probe particles, we observed a lower mass fraction of SVOCs in poly(ethylene glycol) dimethyl ether (MePEG500) probe particles under otherwise identical conditions; this may be due to the lower polarity of the MePEG500 or caused by esterification reactions between the PEG400 and organic acids in the SOA.
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Penglin
authors.initials: P
authors.lastname: Ye
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.|State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry , Chinese Academy of Sciences , Guangzhou 510640, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Ding
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Qing
authors.initials: Q
authors.lastname: Ye
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Ellis S
authors.initials: ES
authors.lastname: Robinson
authors.affiliation: Center for Atmospheric Particle Studies, Carnegie Mellon University , 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Neil M
authors.initials: NM
authors.lastname: Donahue
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D000081008:Bicyclic Monoterpenes; D015335:Molecular Probes / Q000737:chemistry*; D039821:Monoterpenes / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D014835:Volatilization
chemical_list: D000336:Aerosols; D000081008:Bicyclic Monoterpenes; D015335:Molecular Probes; D039821:Monoterpenes; D009930:Organic Chemicals; D011092:Polyethylene Glycols; C005451:alpha-pinene