title: Chemical composition and seasonal variation of acid deposition in Guangzhou, South China: comparison with precipitation in other major Chinese cities.
abstract: With the aim of understanding the origin of acid rains in South China, we analyzed rainwaters collected from Guangzhou, China, between March 2005 and February 2006. The pH of rainwater collected during the monitoring period varied from 4.22 to 5.87; acid rain represented about 94% of total precipitation during this period. The rainwater was characterized by high concentrations of SO(4)(2-), NO(3)(-), Ca(2+), and NH(4)(+). SO(4)(2-) and NO(3)(-), the main precursors of acid rain, were related to the combustion of coal and fertilizer use/traffic emissions, respectively. Ca(2+) and NH(4)(+) act as neutralizers of acid, accounting for the decoupling between high SO(4)(2-) concentrations and relatively high pH in the Guangzhou precipitation. The acid rain in Guangzhou is most pronounced during spring and summer. A comparison with acid precipitation in other Chinese cities reveals a decreasing neutralization capacity from north to south, probably related to the role and origin of alkaline bases in precipitation.
authors.affiliation: Key Laboratory of Isotope Geochronology and Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, PR China. anhuihdy@163.com
authors.forename: De-Yin
authors.initials: DY
authors.lastname: Huang
authors.forename: Yi-Gang
authors.initials: YG
authors.lastname: Xu
authors.forename: Ping'an
authors.initials: P
authors.lastname: Peng
authors.forename: Hui-Huang
authors.initials: HH
authors.lastname: Zhang
authors.forename: Jiang-Bo
authors.initials: JB
authors.lastname: Lan
mesh_terms: D015258:Acid Rain / Q000032:analysis*; D011232:Chemical Precipitation; D002681:China; D002947:Cities; D004784:Environmental Monitoring / Q000379:methods; D004787:Environmental Pollution; D005308:Fertilizers; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009566:Nitrates; D052638:Particulate Matter; D011210:Power Plants; D012621:Seasons; D001335:Vehicle Emissions
chemical_list: D015258:Acid Rain; D005308:Fertilizers; D009566:Nitrates; D052638:Particulate Matter; D001335:Vehicle Emissions