TitleHeterogeneous reactions of particulate matter-bound PAHs and NPAHs with NO3/N2O5, OH radicals, and O3 under simulated long-range atmospheric transport conditions: reactivity and mutagenicity.
Publication TypeJournal Article
Year of Publication2014
AuthorsJariyasopit, N, Zimmermann, K, Schrlau, JE, Arey, J, Atkinson, R, Yu, T-W, Dashwood, RH, Tao, S, Simonich, SLMassey
JournalEnviron Sci Technol
Date Published2014 Sep 02
KeywordsAtmosphere, California, China, Fluorenes, Hydroxyl Radical, Mutagenicity Tests, Mutagens, Nitrates, Nitrogen Oxides, Ozone, Particulate Matter, Polycyclic Aromatic Hydrocarbons, Pyrenes

The heterogeneous reactions of ambient particulate matter (PM)-bound polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs (NPAHs) with NO3/N2O5, OH radicals, and O3 were studied in a laboratory photochemical chamber. Ambient PM2.5 and PM10 samples were collected from Beijing, China, and Riverside, California, and exposed under simulated atmospheric long-range transport conditions for O3 and OH and NO3 radicals. Changes in the masses of 23 PAHs and 20 NPAHs, as well as the direct and indirect-acting mutagenicity of the PM (determined using the Salmonella mutagenicity assay with TA98 strain), were measured prior to and after exposure to NO3/N2O5, OH radicals, and O3. In general, O3 exposure resulted in the highest relative degradation of PM-bound PAHs with more than four rings (benzo[a]pyrene was degraded equally well by O3 and NO3/N2O5). However, NPAHs were most effectively formed during the Beijing PM exposure to NO3/N2O5. In ambient air, 2-nitrofluoranthene (2-NF) is formed from the gas-phase NO3 radical- and OH radical-initiated reactions of fluoranthene, and 2-nitropyrene (2-NP) is formed from the gas-phase OH radical-initiated reaction of pyrene. There was no formation of 2-NF or 2-NP in any of the heterogeneous exposures, suggesting that gas-phase formation of NPAHs did not play an important role during chamber exposures. Exposure of Beijing PM to NO3/N2O5 resulted in an increase in direct-acting mutagenic activity which was associated with the formation of mutagenic NPAHs. No NPAH formation was observed in any of the exposures of the Riverside PM. This was likely due to the accumulation of atmospheric degradation products from gas-phase reactions of volatile species onto the surface of PM collected in Riverside prior to exposure in the chamber, thus decreasing the availability of PAHs for reaction.

Alternate JournalEnviron. Sci. Technol.
PubMed ID25119270
PubMed Central IDPMC4152393
Grant ListP30 ES000210 / ES / NIEHS NIH HHS / United States
P42 ES016465 / ES / NIEHS NIH HHS / United States
P30ES00210 / ES / NIEHS NIH HHS / United States