HR: 0800h
AN: A11A-0851    [Abstracts]
TI: Modeling the SOA Forming Potential of Substituted Dihydrofurans from Alkane + OH Reactions in the Atmosphere
AU: * Jordan, C E
EM: Carolyn.Jordan@unh.edu
AF: Climate Change Research Center, Institute for the Study of Earth Oceans and Space 39 College Rd., Durham, NH 03824 United States
AU: Griffin, R J
EM: rjg@ccrc.sr.unh.edu
AF: Climate Change Research Center, Institute for the Study of Earth Oceans and Space 39 College Rd., Durham, NH 03824 United States
AU: Lim, Y B
EM: Yong.Lim@ucr.edu
AF: Air Pollution Research Center, Trailer 7 University of California, Riverside, CA 92521 United States
AU: Ziemann, P J
EM: Paul.Ziemann@ucr.edu
AF: Air Pollution Research Center, Trailer 7 University of California, Riverside, CA 92521 United States
AU: Atkinson, R
EM: Roger.Atkinson@ucr.edu
AF: Air Pollution Research Center, Fawcett Lab 123 University of California, Riverside, CA 92521 United States
AU: Arey, J
EM: Janet.Arey@ucr.edu
AF: Air Pollution Research Center, Fawcett Lab 229 University of California, Riverside, CA 92521 United States
AB: Recent laboratory studies show that δ-hydroxycarbonyls formed in the atmosphere via OH-initiated reactions with alkanes can cyclize then dehydrate to form substituted dihydrofurans. These dihydrofurans are highly reactive, with lifetimes in the atmosphere of 1.3 h (OH), 24 s (NO₃), and 7 min (O₃). The ability of the δ-hydroxycarbonyls to cyclize and dehydrate has been shown to increase with increasing carbon number. Recent laboratory results show that the secondary organic aerosol (SOA) yields from alkanes also increase with carbon number reaching ~53% for C₁₅. The reaction mechanism proposed based on the chamber results is the basis of the modeling study presented here. We have incorporated this proposed mechanism into the Caltech Atmospheric Chemistry Mechanism (CACM). For computational reasons, similar compounds are lumped together and represented by a single suitable compound. In the present case, alkanes are lumped into 3 groups: short chains (≤C₆), medium chains (C₇ - C₁₂), and long chains (≥C₁₃). SOA yields obtained in chamber studies increase dramatically from 0.5% for C₈ to 25% for C₁₂. The most dramatic increase is observed from C₁₁ (8%) to C₁₃ (~50%). This is attributed to the low volatility of first generation products contributing to the SOA from longer chain alkanes. Here we have studied OH reactions with the substituted dihydrofurans for medium (represented by C₁₀) and long (represented by C₁₆) chain alkanes using CACM along with the aerosol partitioning module MPMPO (Model to Predict the Multi-phase Partitioning of Organics). We will present the results of this modeling study, characterizing the influence of substituted dihydrofurans on the SOA forming potential of alkanes.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005