Daytime atmospheric oxidation capacity in four Chinese megacities during the photochemically polluted season: a case study based on box model simulation
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Published:2019-03-20
Issue:6
Volume:19
Page:3493-3513
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ISSN:1680-7324
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Container-title:Atmospheric Chemistry and Physics
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language:en
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Short-container-title:Atmos. Chem. Phys.
Author:
Tan ZhaofengORCID, Lu KedingORCID, Jiang Meiqing, Su Rong, Wang Hongli, Lou ShengrongORCID, Fu QingyanORCID, Zhai Chongzhi, Tan Qinwen, Yue Dingli, Chen Duohong, Wang Zhanshan, Xie Shaodong, Zeng Limin, Zhang Yuanhang
Abstract
Abstract. Atmospheric oxidation capacity is the basis for
converting freshly emitted substances into secondary products and is
dominated by reactions involving hydroxyl radicals (OH) during daytime. In
this study, we present in situ measurements of ROx radical (hydroxy OH,
hydroperoxy HO2, and organic peroxy RO2) precursors and products;
the measurements are carried out in four Chinese megacities (Beijing,
Shanghai, Guangzhou, and Chongqing) during photochemically polluted seasons.
The atmospheric oxidation capacity is evaluated using an observation-based
model and radical chemistry precursor measurements as input. The radical
budget analysis illustrates the importance of HONO and HCHO photolysis,
which account for ∼50 % of the total primary radical
sources. The radical propagation is efficient due to abundant NO in urban
environments. Hence, the production rate of secondary pollutants, that is,
ozone (and fine-particle precursors (H2SO4, HNO3, and
extremely low volatility organic compounds, ELVOCs) is rapid, resulting in
secondary air pollution. The ozone budget demonstrates its high production
in urban areas; also, its rapid transport to downwind areas results in rapid
increase in local ozone concentrations. The O3–NOx–VOC (volatile
organic compound) sensitivity tests show that ozone production is
VOC-limited and that alkenes and aromatics should be mitigated first for
ozone pollution control in the four studied megacities. In contrast,
NOx emission control (that is, a decrease in NOx) leads to more
severe ozone pollution. With respect to fine-particle pollution, the role of
the HNO3–NO3 partitioning system is investigated using a thermal
dynamic model (ISORROPIA 2). Under high relative humidity (RH) and
ammonia-rich conditions, nitric acid converts into nitrates. This study
highlights the efficient radical chemistry that maintains the atmospheric
oxidation capacity in Chinese megacities and results in secondary pollution
characterized by ozone and fine particles.
Funder
National Natural Science Foundation of China
Publisher
Copernicus GmbH
Subject
Atmospheric Science
Reference96 articles.
1. Brune, W. H., Baier, B. C., Thomas, J., Ren, X., Cohen, R. C., Pusede, S.
E., Browne, E. C., Goldstein, A. H., Gentner, D. R., Keutsch, F. N.,
Thornton, J. A., Harrold, S., Lopez-Hilfiker, F. D., and Wennberg, P. O.:
Ozone production chemistry in the presence of urban plumes, Faraday
Discuss., 189, 161–189, https://doi.org/10.1039/C5FD00204D,
2016. 2. Carter, W. P.: Updated maximum incremental reactivity scale and hydrocarbon
bin reactivities for regulatory applications, California Air Resources Board
Contract, 07-339, 2009. 3. Chan, C. K. and Yao, X.: Air pollution in mega cities in China, Atmos.
Environ., 42, 1–42, https://doi.org/10.1016/j.atmosenv.2007.09.003, 2008. 4. Chen, W., Shao, M., Wang, M., Lu, S., Liu, Y., Yuan, B., Yang, Y., Zeng, L.,
Chen, Z., Chang, C.-C., Zhang, Q., and Hu, M.: Variation of ambient carbonyl
levels in urban Beijing between 2005 and 2012, Atmos. Environ., 129,
105–113, https://doi.org/10.1016/j.atmosenv.2015.12.062, 2016. 5. Cheng, Y., Zheng, G., Wei, C., Mu, Q., Zheng, B., Wang, Z., Gao, M., Zhang,
Q., He, K., Carmichael, G., Poschl, U., and Su, H.: Reactive nitrogen
chemistry in aerosol water as a source of sulfate during haze events in
China, Sci. Adv., 2, e1601530, https://doi.org/10.1126/sciadv.1601530, 2016.
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