| Title | Ambient nitro-aromatic compounds - biomass burning versus secondary formation in rural China |
| Authors | Salvador, Christian Mark Garcia Tang, Rongzhi Priestley, Michael Li, Linjie Tsiligiannis, Epameinondas Le Breton, Michael Zhu, Wenfei Zeng, Limin Wang, Hui Yu, Ying Hu, Min Guo, Song Hallquist, Mattias |
| Affiliation | Univ Gothenburg, Dept Chem & Mol Biol, Gothenburg, Sweden Peking Univ, Coll Environm Sci & Engn, Beijing 100871, Peoples R China Shanghai Acad Environm Sci, Shanghai 200233, Peoples R China Peking Univ, State Key Joint Lab Environm Simulat & Pollut Con, Int Joint Lab Reg Pollut Control, Minist Educ IJRC,Coll Environm Sci & Engn, Beijing 100871, Peoples R China Volvo Grp Trucks & Technol Method & Tech Dev, Gothenburg, Sweden |
| Issue Date | 2-Feb-2021 |
| Publisher | ATMOSPHERIC CHEMISTRY AND PHYSICS |
| Abstract | Nitro-aromatic compounds (NACs) were measured hourly at a rural site in China during wintertime to monitor the changes due to local and regional impacts of biomass burning (BB). Concurrent and continuous measurements of the concentrations of 16 NACs in the gas and particle phases were performed with a time-of-flight chemical ionization mass spectrometer (CIMS) equipped with a Filter Inlet for Gases and AEROsols (FIGAERO) unit using iodide as the reagent ion. NACs accounted for <2 % of the mass concentration of organic matter (OM) and total particulate matter (PM), but the total particle mass concentrations of these compounds can reach as high as 1000 ng m(-3) (299 ng m(-3) avg), suggesting that they may contribute significantly to the radiative forcing effects of atmospheric particles. Levels of gas-phase NACs were highest during the daytime (15:00-16:00 local time, LT), with a smaller night-time peak around 20:00LT. Box-model simulations showed that this occurred because the rate of NAC production from gas-phase sources exceeded the rate of loss, which occurred mainly via the OH reaction and to a lesser degree via photolysis. Data gathered during extended periods with high contributions from primary BB sources (resulting in 40 %-60 % increases in NAC concentrations) were used to characterize individual NACs with respect to gas-particle partitioning and the contributions of regional secondary processes (i.e. photochemical smog). On days without extensive BB, secondary formation was the dominant source of NACs, and NAC levels correlated strongly with the ambient ozone concentration. Analyses of individual NACs in the regionally aged plumes sampled on these days allowed precursors such as phenol and catechol to be linked to their NAC derivatives (i.e. nitrophenol and nitrocatechol). Correlation analysis using the high time resolution data and box-model simulation results constrained the relationships between these compounds and demonstrated the contribution of secondary formation processes. Furthermore, 13 of 16 NACS were classified according to primary or secondary formation process. Primary emission was the dominant source (accounting for 60 %-70 % of the measured concentrations) of 5 of the 16 studied NACs, but secondary formation was also a significant source. Photochemical smog thus has important effects on brown carbon levels even during wintertime periods dominated by primary air pollution in rural China. |
| URI | http://hdl.handle.net/20.500.11897/604950 |
| ISSN | 1680-7316 |
| DOI | 10.5194/acp-21-1389-2021 |
| Indexed | SCI(E) |
| Appears in Collections: | 环境科学与工程学院 环境模拟与污染控制国家重点联合实验室 |
