title: [Seasonal variation of carcinogenic heavy metals in PM2.5 and source analysis in Beijing].
abstract: During April, July, October 2009 and January 2010, daily (24-h average) PM2.5 samples were collected at urban sites in Beijing and 29 metal elements were analyzed by the ICP-MS. The characteristics of 7 carcinogenic heavy metal mass concentrations, enrichment, and possible sources were discussed. The annual average concentrations of As, Cd, Co, Cr, Ni, Pb and Se were (11.6 +/- 14.0), (2.6 +/- 2.4), (1.0 +/- 0.7), (11.3 +/- 9.4), (4.0 +/- 2.4), (142.5 +/- 98.9) and (3.3 +/- 2.2) ng m(-3), respectively. Only annual average concentration of As exceeded WHO standard by a factor of 0.8. Higher enrichment factors of As, Cd, Pb and Se were found and their enrichment factors exceeded 500. Their enrichment factors in summer were much higher than those in other seasons. The local coal combustion and vehicle exhaust should be the dominant sources for the above four carcinogenic heavy metals in spring, autumn and winter, while regional transportation contributed more in summer.
authors.forename: Jun
authors.initials: J
authors.lastname: Tao
authors.forename: Ren-Jian
authors.initials: RJ
authors.lastname: Zhang
authors.forename: Jing-Chun
authors.initials: JC
authors.lastname: Duan
authors.forename: Jun-Shan
authors.initials: JS
authors.lastname: Jing
authors.forename: Li-Hua
authors.initials: LH
authors.lastname: Zhu
authors.forename: Zhong-Ming
authors.initials: ZM
authors.lastname: Chen
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhao
authors.forename: Jun-Ji
authors.initials: JJ
authors.lastname: Cao
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002681:China; D002947:Cities; D003031:Coal; D004784:Environmental Monitoring; D019216:Metals, Heavy / Q000032:analysis*; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D003031:Coal; D019216:Metals, Heavy; D052638:Particulate Matter; D001335:Vehicle Emissions