Secondary Organic Aerosol from Photooxidation of Polycyclic Aromatic Hydrocarbons

Abstract

Secondary organic aerosol (SOA) formation from the photooxidation of five polycyclic aromatic hydrocarbons (PAHs, naphthalene, 1- and 2-methylnaphthalene, acenaphthylene, and acenaphthene) was investigated in a 9-m(3) chamber in the presence of nitrogen oxides and the absence of seed aerosols. Aerosol size distributions and PAH decay were monitored by a scanning mobility particle sizer and a gas chromatograph with a flame ionization detector. Over a wide range of conditions, the aerosol yields for the investigated PAHs were observed to be in the range of 2-22%. The observed evolution of aerosol and PAH decay indicate that light and oxidant sources influence the time required to form aerosol and the required threshold reacted concentration of the PAHs. The SOA yields also were related to this induction period and the hydroxyl radical concentrations, particularly for smaller aerosol loadings (<∼6 μg m(-3)). Estimation of SOA production from oxidation of PAHs emitted from mobile sources in Houston shows that PAHs could account for more than 10% of the SOA formed from emissions from mobile sources in this region.

The formation of SOA and chemical tracer compounds from the photooxidation of naphthalene and its methyl analogs in the presence and absence of nitrogen oxides

“…For experiments at high NO x levels, Chan et al (2009) provide parameterization for SOA partitioning for naphthalene as, α 1 0.21, α 2 1.07, K 1 0.59, K 2 0.0037, for the two product model. Aerosol yields have also been examined by Shakya and Griffin (2010), who in the experimental yield data they present show a nearly constant yield of 0.15 over organic aerosol concentrations from 5-25 µg m −3 , indicating that partitioning may be playing a minor role in the aerosol products generated. Nonetheless, Shakya and Griffin (2010) present parameters for a two-product model for naphthalene SOA formation that assumes partitioning.…”

“…The formation of secondary organic aerosol from the photooxidation of naphthalene has previously been shown to occur both in the presence and absence of NO x (Chan et al, 2009;Kautzman et al, 2010;Shakya and Griffin, 2010). While Kautzman et al (2010) focused on the identification of individual chemical products in the gas and particle phase, Chan et al (2009) In the studies of Chan et al (2009), aerosol yields were measured under high-NO x conditions with aerosol loadings ranging from 10-40 µg m −3 with evidence for semivolatile partitioning from these experiments.…”

Open burning of rice, corn and wheat straws: primary emissions, photochemical aging, and secondary organic aerosol formation

“…In this study, 20 NMOGs which have been used to estimate SOA yields by previous work (Ng et al, 2007;Chan et al, 2009Chan et al, , 2010Hildebrandt et al, 2009;Gómez Alvarez et al, 2009;Shakya and Griffin, 2010;Chhabra et al, 2011;Nakao et al, 2011;Borras and Tortajada-Genaro, 2012;Yee et al, 2013;Lim et al, 2013) were quantified using PTR-TOF-MS, and the applied SOA yields are summarized in Table S2. The mass concentration of SOA ([SOA] predicted , µg m −3 ) formed from these 20 precursors can be estimated using Eq.…”

Naphthalene SOA: redox activity and naphthoquinone gas–particle partitioning

“…However, due to high SOA mass yields, naphthalene itself has a potential to contribute considerably to particulate mass in areas with strong PAH emissions. For example, it has been estimated that naphthalene, 1-and 2-methylnaphthalene, acenaphthalene and acenaphthylene from mobile sources could contribute 37-162 kg m −3 d −1 of SOA in Houston, Texas, compared to a total SOA estimate of 268 kg m −3 d −1 from mobile sources, with a substantial fraction (36-48 %) of the PAH SOA mass coming from naphthalene oxidation (Shakya and Griffin, 2010). For diesel exhaust, it was estimated that of SOA production from oxidation of light aromatics, PAHs, and long-chain alkanes, 58 % of the aerosol produced arises from PAH precursor species (Chan et al, 2009).…”