title: Molecular Composition and Volatility of Organic Aerosol in the Southeastern U.S.: Implications for IEPOX Derived SOA.
abstract: We present measurements as part of the Southern Oxidant and Aerosol Study (SOAS) during which atmospheric aerosol particles were comprehensively characterized. We present results utilizing a Filter Inlet for Gases and AEROsol coupled to a chemical ionization mass spectrometer (CIMS). We focus on the volatility and composition of isoprene derived organic aerosol tracers and of the bulk organic aerosol. By utilizing the online volatility and molecular composition information provided by the FIGAERO-CIMS, we show that the vast majority of commonly reported molecular tracers of isoprene epoxydiol (IEPOX) derived secondary organic aerosol (SOA) is derived from thermal decomposition of accretion products or other low volatility organics having effective saturation vapor concentrations <10(-3) μg m(-3). In addition, while accounting for up to 30% of total submicrometer organic aerosol mass, the IEPOX-derived SOA has a higher volatility than the remaining bulk. That IEPOX-SOA, and more generally bulk organic aerosol in the Southeastern U.S. is comprised of effectively nonvolatile material has important implications for modeling SOA derived from isoprene, and for mechanistic interpretations of molecular tracer measurements. Our results show that partitioning theory performs well for 2-methyltetrols, once accretion product decomposition is taken into account. No significant partitioning delays due to aerosol phase or viscosity are observed, and no partitioning to particle-phase water or other unexplained mechanisms are needed to explain our results.
authors.affiliation: Department of Atmospheric Sciences, University of Washington , Seattle, Washington 98195, United States.
authors.forename: F D
authors.initials: FD
authors.lastname: Lopez-Hilfiker
authors.affiliation: Department of Atmospheric Sciences, University of Washington , Seattle, Washington 98195, United States.
authors.forename: C
authors.initials: C
authors.lastname: Mohr
authors.affiliation: Department of Chemistry, University of Washington , Seattle, Washington 98195, United States.
authors.forename: E L
authors.initials: EL
authors.lastname: D'Ambro
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg , 41296 Gothenburg, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Lutz
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27516, United States.
authors.forename: T P
authors.initials: TP
authors.lastname: Riedel
authors.affiliation: Department of Atmospheric Sciences, University of Washington , Seattle, Washington 98195, United States.
authors.forename: C J
authors.initials: CJ
authors.lastname: Gaston
authors.affiliation: Department of Chemistry, University of Helsinki , Helsinki, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Iyer
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27516, United States.
authors.forename: Z
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27516, United States.
authors.forename: A
authors.initials: A
authors.lastname: Gold
authors.affiliation: Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27516, United States.
authors.forename: J D
authors.initials: JD
authors.lastname: Surratt
authors.affiliation: Department of Atmospheric Sciences, University of Washington , Seattle, Washington 98195, United States.
authors.forename: B H
authors.initials: BH
authors.lastname: Lee
authors.affiliation: Department of Chemistry, University of Helsinki , Helsinki, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Kurten
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.|Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: W W
authors.initials: WW
authors.lastname: Hu
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.|Cooperative Institute for Research in Environmental Sciences, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: J
authors.initials: J
authors.lastname: Jimenez
authors.affiliation: Department of Chemistry and Molecular Biology, University of Gothenburg , 41296 Gothenburg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Hallquist
authors.affiliation: Department of Atmospheric Sciences, University of Washington , Seattle, Washington 98195, United States.
authors.forename: J A
authors.initials: JA
authors.lastname: Thornton
mesh_terms: D000336:Aerosols / Q000032:analysis / Q000737:chemistry*; D001272:Atmosphere / Q000737:chemistry; D002070:Butadienes / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D005740:Gases; D045782:Hemiterpenes / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D010420:Pentanes / Q000737:chemistry; D015144:Southeastern United States; D014835:Volatilization
chemical_list: D000336:Aerosols; D002070:Butadienes; D005740:Gases; D045782:Hemiterpenes; D010420:Pentanes; C005059:isoprene