title: Evaluation of the behavior of clouds in a region of severe acid rain pollution in southern China: species, complexes, and variations.
abstract: Cloud samples were collected during the summer of 2011 and the spring of 2012 at a high-elevation site in southern China in an effort to examine the chemical characteristics of acid clouds. In total, 141 cloud samples were collected during 44 cloud events over the observation period. The dominant ionic species were SO4(2-), NH4(+), and NO3(-), contributing approximately 75% of the total inorganic ion concentration. The primary acidifying factors were sulfate and nitrate, and the primary neutralizing factors were ammonium and calcium. The volume-weighted mean (VWM) pH of the cloud water was 3.79, indicating an acidic nature. In these cloud samples, Zn and Al exhibited the highest trace metal concentrations, contributing approximately 60% of the total trace element concentration. Toxic metals, such as Pb, Ba, As, and Cr, were detected at high concentrations, indicating potential hazards for human health, vegetation, and waters in this region. Visual MINTEQ 3.0 results revealed that the majority of Zn(II) and Pb(II) existed in the form of free ions. The behavior of Al, however, differed from the behaviors of zinc and lead. The temporal variation in cloud chemistry indicated that temperature, sandstorms, and long-range transport could affect the concentrations of species. During the lifetime of a cloud event, the concentrations of the chemical species were controlled by the transfer of gases or particles to liquid droplets.
authors.affiliation: School of Environmental Science and Engineering, Shandong University, Jinan, 250100, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Taixing
authors.initials: T
authors.lastname: Yue
authors.forename: Xueqiao
authors.initials: X
authors.lastname: Yang
authors.forename: Likun
authors.initials: L
authors.lastname: Xue
authors.forename: Wenxing
authors.initials: W
authors.lastname: Wang
mesh_terms: D015258:Acid Rain / Q000032:analysis*; D000393:Air Pollutants / Q000032:analysis*; D000818:Animals; D002681:China; D004784:Environmental Monitoring; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019216:Metals, Heavy / Q000032:analysis; D009566:Nitrates / Q000032:analysis; D012621:Seasons; D013431:Sulfates / Q000032:analysis; D014131:Trace Elements / Q000032:analysis; D014867:Water / Q000737:chemistry
chemical_list: D015258:Acid Rain; D000393:Air Pollutants; D019216:Metals, Heavy; D009566:Nitrates; D013431:Sulfates; D014131:Trace Elements; D014867:Water