title: Quantification of Gas-Wall Partitioning in Teflon Environmental Chambers Using Rapid Bursts of Low-Volatility Oxidized Species Generated in Situ.
abstract: Partitioning of gas-phase organic compounds to the walls of Teflon environmental chambers is a recently reported phenomenon than can affect the yields of reaction products and secondary organic aerosol (SOA) measured in laboratory experiments. Reported time scales for reaching gas-wall partitioning (GWP) equilibrium (τGWE) differ by up to 3 orders of magnitude, however, leading to predicted effects that vary from substantial to negligible. A new technique is demonstrated here in which semi- and low-volatility oxidized organic compounds (saturation concentration c* < 100 μg m(-3)) were photochemically generated in rapid bursts in situ in an 8 m(3) environmental chamber, and then their decay in the absence of aerosol was measured using a high-resolution chemical ionization mass spectrometer (CIMS) equipped with an "inlet-less" NO3(-) ion source. Measured τGWE were 7-13 min (rel. std. dev. 33%) for all compounds. The fraction of each compound that partitioned to the walls at equilibrium follows absorptive partitioning theory with an equivalent wall mass concentration in the range 0.3-10 mg m(-3). Measurements using a CIMS equipped with a standard ion-molecule reaction region showed large biases due to the contact of compounds with walls. On the basis of these results, a set of parameters is proposed for modeling GWP in chamber experiments.
authors.affiliation: Cooperative Institute for Research in Environmental Sciences (CIRES) , Boulder, Colorado 80309, United States.|Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Jordan E
authors.initials: JE
authors.lastname: Krechmer
authors.affiliation: Cooperative Institute for Research in Environmental Sciences (CIRES) , Boulder, Colorado 80309, United States.|Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Demetrios
authors.initials: D
authors.lastname: Pagonis
authors.affiliation: Cooperative Institute for Research in Environmental Sciences (CIRES) , Boulder, Colorado 80309, United States.|Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Ziemann
authors.affiliation: Cooperative Institute for Research in Environmental Sciences (CIRES) , Boulder, Colorado 80309, United States.|Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Jimenez
mesh_terms: D000336:Aerosols; D000393:Air Pollutants; D009930:Organic Chemicals / Q000737:chemistry; D011138:Polytetrafluoroethylene; D014835:Volatilization
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D009930:Organic Chemicals; D011138:Polytetrafluoroethylene