College of Environmental Science and Engineering, Nankai University, Tianjin, People's Republic of China.
The State Environment Protection Key Laboratory of Urban Particulate Air Pollution and Prevention, Tianjin, People's Republic of China.
J Air Waste Manag Assoc. 2019 Dec;69(12):1452-1466. doi: 10.1080/10962247.2019.1674750. Epub 2019 Nov 4.
To investigate the effect of atmospheric particulates on the chemistry and acidity of rainwater during the washout process in areas with highly acidic rainfall, rainwater and particulates (before, during and after rain) were sampled and analyzed from June 2008 to June 2009 in the Yangtze River Delta region, China. The volume-weighted mean pH of the rainwater was only 4.44 in Hangzhou, and the average concentrations of TSP (total-suspended particulates) and PM (particulates with aerodynamic equivalent diameters of less than 10 μm) during the study period were 191 μg/m and 155 μg/m, respectively. The measured acid buffering capacities of PM and TSP were 1.31 ± 0.45 and 1.61 ± 0.84 ml/mg, on average, respectively, indicating that both had a certain acid buffering capacity. Rain appeared to have a pronounced scouring effect on particulates, except for F and Cl in PM. Upon combining the correlation analysis between ions in particulates and rainwater with Enrichment Factor and Principal Component Analysis of the rainwater chemistry, the results suggested that the components of rainwater were mainly derived from washout processes acting on particulates from crustal dust and building industry sources (Ca), marine sources (Na, K (in spring), Mg and Cl) and anthropogenic sources, especially secondary aerosols emitted from agricultural land, motor vehicles and industrial plants (NO, SO, and NH). The F in rainwater was mainly contributed by gaseous pollutants, such as HF from cooling systems, coal burning and surrounding factories. The interaction between particulates and rain in areas with highly acidic rainfall include the following: rain appears to have a pronounced scouring effect on most components in the particulates; the components of the rainwater are mainly derived from washout processes acting on PM contributed by crustal dust, sea salt and secondary aerosol subcloud; and the acid buffering capacities of PM and TSP in Hangzhou are 1.31 ± 0.45 and 1.61 ± 0.84 ml/mg, respectively, and had a certain acid buffering capacity toward rainwater.
为了研究在强酸雨地区的冲洗过程中大气颗粒物对雨水化学和酸度的影响，我们于 2008 年 6 月至 2009 年 6 月在长江三角洲地区采集和分析了雨水和颗粒物（雨前、雨中、雨后）。杭州雨水的体积加权平均 pH 值仅为 4.44，研究期间总悬浮颗粒物（TSP）和粒径小于 10μm 的颗粒物（PM）的平均浓度分别为 191μg/m 和 155μg/m。PM 和 TSP 的实测酸缓冲能力平均分别为 1.31±0.45 和 1.61±0.84ml/mg，表明两者均具有一定的酸缓冲能力。除了 PM 中的 F 和 Cl 之外，降雨对颗粒物似乎具有明显的冲刷作用。结合颗粒物与雨水之间离子的相关性分析，以及雨水化学的富集因子和主成分分析，结果表明雨水成分主要来源于对来自地壳灰尘和建筑工业源（Ca）、海洋源（Na、K（春季）、Mg 和 Cl）和人为源，特别是来自农田、机动车和工业工厂的二次气溶胶（NO、SO 和 NH）的颗粒物的冲洗过程。雨水中的 F 主要来自冷却系统、燃煤和周围工厂等气态污染物中的 HF。强酸雨地区颗粒物与雨水的相互作用包括：降雨对颗粒物中大多数成分似乎具有明显的冲刷作用；雨水成分主要来源于对由地壳灰尘、海盐和云下二次气溶胶贡献的 PM 的冲洗过程；以及杭州 PM 和 TSP 的酸缓冲能力分别为 1.31±0.45 和 1.61±0.84ml/mg，对雨水具有一定的酸缓冲能力。
