3/11/2024 0 Comments Fwsim london 2015![]() ![]() The concentration weighted trajectory (CWT) analysis demonstrated that regional transport from provinces that surround the Yellow and Bohai Seas contributed more primary NPs to Beijing. The industry source contributed 30 % and 9 % to DNP and MDNP, respectively, which was non-negligible. By estimating the primarily emitted phenol from the ratio of phenol/CO from freshly emitted vehicle exhaust, this study proposed that oxidation of primary phenol contributes much more nitrophenol (37 %) than that from benzene oxidation ( 50 %) to the gas-phase NPs. The phenoxy radical consequently reacted with NO2, and produced nitrophenol. Phenol-OH reaction was the predominant loss pathway (46.7 %) during the heavy pollution episode, which produced phenoxy radical (C6H5O). Our results showed that secondary formation contributed 38 %, 9 %, 5 %, 17 % and almost 100 % of the ambient nitrophenol (NP), methyl-nitrophenol (MNP), dinitrophenol (DNP), methyl-dinitrophenol (MDNP or DNOC), and dimethyl-nitrophenol (DMNP). In addition, the primary sources of NPs were resolved by non-negative matrix factorization (NMF) model. A box model was applied to simulate the secondary formation process of NPs. To investigate the composition, variation, and sources of nitrated phenols (NPs) in the winter of Beijing, gas-phase NPs were measured by using a chemical ionization long time-of-flight mass spectrometer (CI-LToF-MS). ![]()
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