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Liao B.-T.,Guangzhou Luogang Meteorology | Wu D.,Jinan University | Wu D.,Guangzhou Institute of Tropical and Marine Meteorology | Chen J.,Nanyang Technological University | And 3 more authors.
Zhongguo Huanjing Kexue/China Environmental Science | Year: 2015

126 groups of size-segregated aerosol samples collected from Guangzhou, Shenzhen, Haikou and some other regions in South China during 1998~2010 were utilized to characterize the temporal-spatial variations of size-resolved mass concentrations of AEC and inorganic water-soluble ions. Notable regional differences were displayed, the mass concentrations of Na+ and Cl- at different sites presented the characteristics of island > coastal > rural > urban. To the contrary, mass concentrations of other major ions and AEC were in the order of urban > rural > coastal > island sites. During different observation periods, size-resolved mass concentrations of AEC showed a similar bimodal pattern for all sites, with the prominent peak located in the range of 0.43~0.65μm and the smaller peak distributed in a larger size range (4.7~5.8 μm). The vertical distributions of AEC and inorganic water-soluble ions can be categorized into three types according to the corresponding size-resolved mass concentrations. Specifically, the secondary ions (SO42-, NO3- and NH4+) showed a distinct three-peak pattern, double-peak structures were found in the results of F-, Ca2+, Mg2+, Na+ and Cl-, both K+ and AEC displayed a significant single peak in the fine-particle mode. The mass concentrations of AEC and inorganic water-soluble ions varied with the variation of height. Precipitations played a crucial role in the removal of aerosol particles larger than 1 μm, especially on the size bins of 1.1~2.1 μm. In local aerosol pollution episodes, the size-resolved mass concentration of AEC had a pronounced unimodal pattern within the submicron size ranges. ©, 2015, Chinese Society for Environmental Sciences. All right reserved.


Liao B.,Guangzhou Luogang Meteorology | Liao B.,Guangzhou Institute of Tropical and Marine Meteorology | Wu D.,Jinan University | Wu D.,Guangzhou Institute of Tropical and Marine Meteorology | And 4 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2014

In this study, hourly water-soluble inorganic ions and related gaseous pollutants were continuously measured from December 2009 to December 2011 in Guangzhou, and their pollution characteristics were characterized. Results showed that the seasonal variation of the mass concentrations of PM2.5, SO4 2-, NH4 + and NO3 - was winter > autumn > spring > summer, autumn > winter > spring > summer, winter > autumn > spring > summer, and winter > spring > autumn > summer, respectively. The sum of SO4 2-, NH4 + and NO3 - in PM2.5 was in the order of winter > spring > autumn > summer. The diurnal variation of sulfate oxygenation efficiency (SOR) was greater than 0.1, and the values of SOR in autumn and winter were higher than those in spring and summer, in accord with the variations of SO4 2- concentrations. Differently, the diurnal variation of nitrate oxygenation efficiency (NOR) showed a single peak at 6: 00 LT and a trough at 14: 00 LT. The values of NOR in spring and winter were higher than those in summer and autumn, similar to the trend of the seasonal variation of NO3 - concentrations. The monthly means of NH3/NH4 + in Guangzhou were larger than 1 except from October to December. During haze days, SO4 2-, NO3 -, NH4 +, SOR, NOR and NH3/NH4 + were well correlated with visibility, implying the strong association between low visibility events in Guangzhou and formation of the secondary inorganic ions.

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