DOI: 10.1016/j.atmosres.2017.10.016
Scopus记录号: 2-s2.0-85033581160
论文题名: Ion balance and acidity of size-segregated particles during haze episodes in urban Beijing
作者: Tian S. ; Pan Y. ; Wang Y.
刊名: Atmospheric Research
ISSN: 1698095
出版年: 2018
卷: 201 起始页码: 159
结束页码: 167
语种: 英语
英文关键词: Acidity
; Haze
; Ion balance
; Size distribution
Scopus关键词: Acidity
; Ions
; Particle size
; Size distribution
; Accumulation modes
; Aerodynamic diameters
; Haze
; Homogeneous reaction
; Ion balance
; Presence of water
; Rich conditions
; Submicron aerosol
; Aerosols
; acidity
; aerosol
; concentration (composition)
; haze
; ion
; particle size
; size distribution
; urban area
; Beijing [Beijing (ADS)]
; Beijing [China]
; China
英文摘要: In this study, we investigated how the ion balance causes variations in size segregated aerosol acidity and atmospheric processing on clean versus hazy days using a 9-stage sampler. We calculated the ratios (in charge equivalents, RC/A) between measured cations (Na+, NH4 +, K+, Mg2 +, and Ca2 +) and anions (SO4 2 −, NO3 − and Cl−) for different aerosol size fractions. The ratios were typically close to unity in the accumulation mode (0.65–2.1 μm), and increased significantly when the particle size increased or decreased. In the coarse size range (aerodynamic diameter > 2.1 μm), high RC/A values were most likely caused by the undetermined CO3 2– and HCO3 – content of the mineral dust. In contrast, the high RC/A values for submicron aerosols (< 1.1 μm) were likely caused by the presence of water-soluble organic anions. The RC/A values for all size fractions were lower on hazy days than clean days, indicating that aerosol acidity was enhanced on polluted days. Simiar temporal trend between RC/A and in-situ pH indicated that RC/A was a good indicator of aerosol acidity in fine mode aerosol. The SO4 2 − and NO3 − contents in fine particles were completely neutralized as the RC/A values for PM2.1 approached unity, and mean values of RC/A were 1.34 and 1.16 during the transition and polluted periods, respectively. The lowest RC/A values were observed in the size fraction with the highest concentrations of SO4 2 −, NO3 − and NH4 + (SNA) and concentrations of SNA increased with the increasing aerosol acidity. Significant correlations between [NO3 −]/[SO4 2 −] and [NH4 +]/[SO4 2 −] during NH4 +-rich conditions in fine size fractions indicated fine mode NO3 − in Beijing was mainly formed by gas-phase homogeneous reaction between the ambient NH3 and HNO3. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/108997
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
There are no files associated with this item.
作者单位: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of SciencesBJ 100029, China
Recommended Citation:
Tian S.,Pan Y.,Wang Y.. Ion balance and acidity of size-segregated particles during haze episodes in urban Beijing[J]. Atmospheric Research,2018-01-01,201