HR: 0800h
AN: A51A-0028    [Abstracts]
TI: Secondary organic aerosol formation from the oxidation of polycyclic aromatic hydrocarbons with two aromatic rings
AU: * Shakya, K M
EM: kabin.shakya@unh.edu
AF: Climate Change Research Center, University of New Hampshire, 39 College Road, Durham, NH 03824,
AU: Griffin, R J
EM: rjg@gust.sr.unh.edu
AF: Climate Change Research Center, University of New Hampshire, 39 College Road, Durham, NH 03824,
AB: Polycyclic aromatic hydrocarbons (PAHs) are products of incomplete combustion and are ubiquitous in the environment. In the atmosphere, gas-phase reactions of PAHs with two aromatic rings with hydroxyl radicals (OH) lead to products that partition to the aerosol phase, forming secondary organic aerosol (SOA). The main objective of this study is to quantify the conversion of gas-phase PAHs with two aromatic rings into particle-phase species through the SOA yield. Eight experiments were conducted on each of the following PAHs: naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, acenaphthalene, acenaphthylene, and fluorene. Experiments were performed in a 9-m³ Teflon chamber, at an initial hydrocarbon to nitric oxide ratio of approximately five, and using hydrogen peroxide as the OH source. The experiments were initiated by illuminating germicidal lamps to drive photochemical reactions and were terminated when the SOA formation reached a plateau. During the experiments, PAH mixing ratios, aerosol particle size distributions and number concentrations, oxides of nitrogen mixing ratios, and ozone mixing ratios were monitored by a gas chromatograph with a flame ionization detector, a scanning mobility particle sizer spectrometer, a chemiluminescence analyzer, and a photometric analyzer, respectively. Results indicate SOA yields ranging from 0.02 to 0.12 over an organic aerosol mass concentration range of 2 to 15 μ g m^-3. Peak aerosol mode diameters were in the range of 60 to 80 nm. An attempt to determine the relationship between yields and PAH structure will be made.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 3311 Clouds and aerosols
DE: 4801 Aerosols (0305, 4906)
DE: 4906 Aerosols (0305, 4801)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting