Measurement report: Online measurement of gas-phase nitrated phenols utilizing a CI-LToF-MS: primary sources and secondary formation

Abstract. To investigate the composition, variation, and sources of nitrated phenols (NPs) in winter Beijing, gas-phase NPs were measured by a chemical ionization long time-of-flight mass spectrometer (CI-LToF-MS). A box model was applied to simulate secondary formation process NPs. In addition, primary resolved non-negative matrix factorization (NMF) model. Our results showed that contributed 38 %, 9 5 17 almost 100 % nitrophenol (NP), methyl-nitrophenol (MNP), dinitrophenol (DNP), methyl-dinitrophenol (MDNP or DNOC), dimethyl-nitrophenol (DMNP) concentrations. The phenol–OH reaction predominant loss pathway (46.7 %) during heavy pollution episode, which produced phenoxy radical (C6H5O). consequently reacted with NO2 nitrophenol. By estimating primarily emitted phenol from ratio phenol/CO freshly vehicle exhaust, this study proposed oxidation contributes much more (37 than benzene (<1 Beijing. latter widely used models might lead great uncertainties. source apportionment NMF indicated importance combustion (>50 industry 30 DNP MDNP, respectively, non-negligible. concentration weighted trajectory (CWT) analysis demonstrated regional transport provinces surround Yellow Bohai seas Both at either local scale should be considered when making control policies