title: Impact of long-range transport and under-cloud scavenging on precipitation chemistry in East China.
abstract: BACKGROUND
  Two hundred twenty-five precipitation samples were collected at high- (summit, 1,534 m ASL) and low-elevation (base, 218 m ASL) sites between 2005 and 2008 in eastern China. The present work focused on the roles of long-range transport and under-cloud/boundary layer scavenging on chemical composition of precipitation collected at the two sites.
  
  
  METHODS
  Ionic and trace species were analyzed in 225 precipitation samples. A total of 72 precipitation events occurring simultaneously at the summit and base sites were further examined. Positive matrix factorization (PMF) and backward air mass trajectories were used to identify the sources of precipitation pollutants.
  
  
  RESULTS
  Low pH and high concentrations of ionic and trace species were measured at both sites. Inter-correlations for the simultaneous samples at the two sites were poor for trace elements (-0.07~0.47). A several fold increase in major ion (122~546%) and trace element (261~3,302%) concentrations occurred as the rain fell. Approximately 89% of the air masses responsible for the summit precipitation events were of distance origin. Marine salt, crustal material, fossil fuel burning plus secondary products, and metallic-industry-related factors were identified by PMF, contributing 9.7%, 22.8%, 41.8%, and 25.6%, respectively, to the precipitation pollutants at the summit and 13.3%, 31.9%, 39.6%, and 15.2%, respectively, at the base.
  
  
  CONCLUSIONS
  Long-range atmospheric transport primarily influenced the high and the low site precipitation was strongly influenced by the under-cloud scavenging process of local boundary layer pollutants. Crustal material and fossil fuel burning plus secondary products were the predominant pollution sources in this region.
authors.affiliation: School of Environmental Science and Engineering, Shandong University, Jinan 250100, China.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Aijun
authors.initials: A
authors.lastname: Ding
authors.forename: Xiaohuan
authors.initials: X
authors.lastname: Liu
authors.forename: Jia
authors.initials: J
authors.lastname: Guo
authors.forename: Penghui
authors.initials: P
authors.lastname: Li
authors.forename: Minghu
authors.initials: M
authors.lastname: Sun
authors.forename: Fuling
authors.initials: F
authors.lastname: Ge
authors.forename: Wenxing
authors.initials: W
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002681:China; D004784:Environmental Monitoring / Q000379:methods; D006863:Hydrogen-Ion Concentration; D011891:Rain / Q000737:chemistry*; D012621:Seasons; D001335:Vehicle Emissions / Q000032:analysis; D014873:Water Pollutants / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D014873:Water Pollutants