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© 2021. This work is published under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

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 20:00 LT. 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.

Details

Title
Ambient nitro-aromatic compounds – biomass burning versus secondary formation in rural China
Author
Garcia Salvador, Christian Mark 1   VIAFID ORCID Logo  ; Tang, Rongzhi 2 ; Priestley, Michael 1   VIAFID ORCID Logo  ; Li, Linjie 1   VIAFID ORCID Logo  ; Tsiligiannis, Epameinondas 1   VIAFID ORCID Logo  ; Michael Le Breton 3 ; Zhu, Wenfei 4 ; Zeng, Limin 2 ; Wang, Hui 2 ; Yu, Ying 2 ; Hu, Min 2 ; Guo, Song 5   VIAFID ORCID Logo  ; Hallquist, Mattias 1   VIAFID ORCID Logo 

 Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden 
 College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China 
 Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden; now at: Volvo Group Trucks and Technology Method and Technical Development, Gothenburg, Sweden 
 Shanghai Academy of Environmental Sciences, Shanghai, 200233, China 
 State Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control, Ministry of Education (IJRC), College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, P. R. China 
Pages
1389-1406
Publication year
2021
Publication date
2021
Publisher
Copernicus GmbH
ISSN
16807316
e-ISSN
16807324
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2484728822
Copyright
© 2021. This work is published under https://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.