title: Chemical characteristics of water-soluble ions in particulate matter in three metropolitan areas in the North China Plain.
abstract: PM2.5 and PM10 samples were collected simultaneously in each season in Beijing, Tianjin and Shijiazhuang to identify the characteristics of water-soluble ion compositions in the North China Plain. The water-soluble ions displayed significant seasonal variation. The dominant ions were NO3(-), SO4(2-), NH4(+) and Cl(-), accounting for more than 90% and 86% to the mass of total water-soluble ions in PM2.5 and PM10, respectively. The anion/cation ratio indicated that the ion acidity of each city varied both between sites and seasonally. Over 50% of the ion species were enriched in small particles ≤1 µm in diameter. The [NO3(-)]/[SO4(2-)] ratio indicated that vehicles accounted for the majority of the particulate pollution in Beijing. Shijiazhuang, a city highly reliant on coal combustion, had a higher SO4(2-) concentration.
authors.affiliation: China National Environmental Monitoring Centre, Beijing, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Dao
authors.affiliation: School of Resource and Environmental Sciences, Wuhan University, Wuhan, Hubei, China; Department of Geography, University of California Santa Barbara, Santa Barbara, California, United States of America.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wang
authors.affiliation: China National Environmental Monitoring Centre, Beijing, China.
authors.forename: Yibing
authors.initials: Y
authors.lastname: Lv
authors.affiliation: China National Environmental Monitoring Centre, Beijing, China.
authors.forename: Enjiang
authors.initials: E
authors.lastname: Teng
authors.affiliation: China National Environmental Monitoring Centre, Beijing, China.
authors.forename: Linlin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: China National Environmental Monitoring Centre, Beijing, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D007477:Ions / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons; D014867:Water / Q000737:chemistry*
chemical_list: D000393:Air Pollutants; D007477:Ions; D052638:Particulate Matter; D014867:Water