title: Long-term trends of chemical characteristics and sources of fine particle in Foshan City, Pearl River Delta: 2008-2014.
abstract: Foshan is a major international ceramic center and the most polluted city in the Pearl River Delta (PRD). Here we present the results of the first long-term PM2.5 (particles <2.5μm) sampling and chemical characterization study of the city. A total of 2774 samples were collected at six sites from 2008 to 2014, and analyzed for water soluble species, elements and carbonaceous species. The major constituents of PM2.5 were sulfate, OC (Organic Carbon), nitrate, ammonium and EC (Elemental Carbon), which accounted for 50%-88% of PM2.5. PM2.5 and the most abundant chemical species decreased from 2008 to 2011, but rebounded in 2012-2013. After 2008, the chemical composition of PM2.5 changed dramatically due to the implementation of pollution control measures. From 2008 to 2011, SO4(2-) and NO3(-) were the two largest components; subsequently, however, OC was the largest component. The respective contributions of SO4(2-), NO3(-) and OC to the sum of water soluble species and carbonaceous species were 30.5%, 22.9% and 19.9% in 2008; and 20.2%, 16.5% and 30.2% in 2014. Distinct differences in nitrate and sulfate, and in mass ratio [NO3(-)]/[SO4(2-)] imply that mobile sources tended to more important in Foshan during 2012-2014. The results indicate that pollution control measures implemented during 2008-2014 had a large effect on anthropogenic elements (Pb, As, Cd, Zn and Cu) and water soluble species, but little influence on crustal elements (V, Mn, Ti, Ba and Fe) and carbonaceous species. The PMF method was used for source apportionment of PM2.5. Industry (including the ceramic industry and coal combustion), vehicles and dust were the three most important sources and comprised 39.2%, 20.0% and 18.4% of PM2.5 in 2008, respectively. However, secondary aerosols, vehicles and industry were the three most important sources and comprised 29.5%, 22.4% and 20.4% of PM2.5 in 2014, respectively. During the seven year study interval, the contributions of primary sources (industry and dust) decreased significantly, but secondary sources increased dramatically. Industry, dust and vehicles contributed 36.6μgm(-3), 13.9μgm(-3), and 9.2μgm(-3) to the reduction of PM2.5, respectively.
authors.affiliation: Huairou Eco-Environmental Observatory, College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China; School of Environment, Tsinghua University, Beijing 100084, China; Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Jihua
authors.initials: J
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Jingchun
authors.initials: J
authors.lastname: Duan
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China. Electronic address: Liang@tsinghua.edu.cn.
authors.forename: Yongliang
authors.initials: Y
authors.lastname: Ma
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Kebin
authors.initials: K
authors.lastname: He
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: Foshan Environmental Protection Bureau, Foshan 528000, China.
authors.forename: Si-Xin
authors.initials: SX
authors.lastname: Deng
authors.affiliation: Foshan Environmental Protection Bureau, Foshan 528000, China.
authors.forename: Yan-Ling
authors.initials: YL
authors.lastname: Huang
authors.affiliation: Foshan Environmental Protection Bureau, Foshan 528000, China.
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Si-Tu
mesh_terms: D000397:Air Pollution / Q000032:analysis* / Q000706:statistics & numerical data; D002681:China; D004784:Environmental Monitoring; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry*
chemical_list: D052638:Particulate Matter
keywords: Chemical species; Long-term; PM(2.5); Pearl River delta; Source apportionment