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Characterization of the size-segregated water-soluble inorganic ions in the Jing-Jin-Ji urban agglomeration: Spatial/temporal variability, size distribution and sources
Abstract To investigate the characteristics of aerosols in north China, the samples of water-soluble ions, including anions (F−, Cl−, NO2 −, NO3 −, SO4 2−) and cations (NH4 +, K+, Na+, Ca2+, Mg2+) in 8 size-segregated particle fractions, are collected using a sampler from Sep. 2009 to Aug. 2010 at four sites in urban areas (Beijing, Tianjin and Tangshan) and a background region (Xinglong) in the Jing-Jin-Ji urban agglomeration. High spatial variability is observed between the urban areas and the background region. The results of chemical composition analysis showed that secondary water soluble ions (SO4 2− + NO3 − + NH4 +) (SWSI) composed more than half the total ions, and are mainly found in fine particles (aerodynamic diameters less than 2.1 μm), while Mg2+ and Ca2+ contributed to a large fraction of the total water-soluble ions in coarse particles (aerodynamic diameters greater than 2.1 μm and less than 9.0 μm). The concentrations of SO4 2−, NO3 − and NH4 + are higher in summer and winter and lower in spring and autumn. Mg2+ and Ca2+ are obviously abundant in winter in Beijing, Tianjin and Tangshan. In contrast, Mg2+ and Ca2+ are abundant in autumn in Xinglong. The SWSI showed a bimodal size distribution with the fine mode at 0.43–1.1 μm and the coarse mode at 4.7–5.8 μm, and had different seasonal variations and bimodal shapes. NH4 + played an important role in the size distributions and the formations of SO4 2− and NO3 −. Heterogeneous reaction is the main formation mechanism of SO4 2− and NO3 −, which tended to be enriched in the coarse mode of aerosol. The sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) indicated high photochemical oxidation property over the whole Jing-Jin-Ji urban agglomeration.
Highlights The concentrations of water-soluble ions in the Jing-Jin-Ji urban agglomeration. The spatial variability of those compounds was discussed. The seasonal variations and size distributions of those compounds were discussed. The sources and formation mechanisms of secondary water-soluble ions were discussed.
Characterization of the size-segregated water-soluble inorganic ions in the Jing-Jin-Ji urban agglomeration: Spatial/temporal variability, size distribution and sources
Abstract To investigate the characteristics of aerosols in north China, the samples of water-soluble ions, including anions (F−, Cl−, NO2 −, NO3 −, SO4 2−) and cations (NH4 +, K+, Na+, Ca2+, Mg2+) in 8 size-segregated particle fractions, are collected using a sampler from Sep. 2009 to Aug. 2010 at four sites in urban areas (Beijing, Tianjin and Tangshan) and a background region (Xinglong) in the Jing-Jin-Ji urban agglomeration. High spatial variability is observed between the urban areas and the background region. The results of chemical composition analysis showed that secondary water soluble ions (SO4 2− + NO3 − + NH4 +) (SWSI) composed more than half the total ions, and are mainly found in fine particles (aerodynamic diameters less than 2.1 μm), while Mg2+ and Ca2+ contributed to a large fraction of the total water-soluble ions in coarse particles (aerodynamic diameters greater than 2.1 μm and less than 9.0 μm). The concentrations of SO4 2−, NO3 − and NH4 + are higher in summer and winter and lower in spring and autumn. Mg2+ and Ca2+ are obviously abundant in winter in Beijing, Tianjin and Tangshan. In contrast, Mg2+ and Ca2+ are abundant in autumn in Xinglong. The SWSI showed a bimodal size distribution with the fine mode at 0.43–1.1 μm and the coarse mode at 4.7–5.8 μm, and had different seasonal variations and bimodal shapes. NH4 + played an important role in the size distributions and the formations of SO4 2− and NO3 −. Heterogeneous reaction is the main formation mechanism of SO4 2− and NO3 −, which tended to be enriched in the coarse mode of aerosol. The sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) indicated high photochemical oxidation property over the whole Jing-Jin-Ji urban agglomeration.
Highlights The concentrations of water-soluble ions in the Jing-Jin-Ji urban agglomeration. The spatial variability of those compounds was discussed. The seasonal variations and size distributions of those compounds were discussed. The sources and formation mechanisms of secondary water-soluble ions were discussed.
Characterization of the size-segregated water-soluble inorganic ions in the Jing-Jin-Ji urban agglomeration: Spatial/temporal variability, size distribution and sources
Li, Xingru (author) / Wang, Lili (author) / Ji, Dongsheng (author) / Wen, Tianxue (author) / Pan, Yuepeng (author) / Sun, Ying (author) / Wang, Yuesi (author)
Atmospheric Environment ; 77 ; 250-259
2013-03-20
10 pages
Article (Journal)
Electronic Resource
English
| DOAJ | 2017