Chemical characterization and source apportionment of PM2.5in a semi-arid and petrochemical-industrialized city, Northwest China.
Daily PM2.5samples were collected in 2014 at a suburban petrochemical industrial site and a downtown site in Lanzhou city, Northwest China. Major chemical components in PM2.5, including water-soluble ions, metal elements, and organic and elemental carbon (OC and EC) were determined. The chemical mass closure method and the ISORROPIA II thermodynamic equilibrium model were used to reconstruct PM2.5mass and quantify the combinations of NH4+, SO42-and NO3-to PM2.5. Positive matrix factorization (PMF) model was employed to apportion potential sources of PM2.5. The annual average PM2.5concentration was 93.7±49.6μgm-3at the suburban petrochemical industrial site and 88.9±52.0μgm-3at the urban site, with the highest seasonal average in winter and the lowest in summer at both sites. Mineral dust was identified as the highest contributor to PM2.5in spring, while water-soluble inorganic ions and carbonaceous aerosols were the dominant chemical components in other seasons. The correlation relationships between OC and EC and between K+and EC suggested that coal combustion and vehicle exhaust were the major sources of carbonaceous aerosols in Lanzhou. Six major sources were identified by the PMF model. Coal combustion, soil dust, traffic emissions, and secondary inorganic aerosols were the dominant contributors, together accounting for 82% of PM2.5mass.
Key Laboratory for Environmental Pollution Prediction and Control, Gansu Province, College of Earth and Environmental Science, Lanzhou University, Lanzhou 730000, China.
Yanan
Y
Wang
Key Laboratory for Environmental Pollution Prediction and Control, Gansu Province, College of Earth and Environmental Science, Lanzhou University, Lanzhou 730000, China.
Chenhui
C
Jia
South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou 510655, China.
Jun
J
Tao
Air Quality Research Division, Science & Technology Branch, Environment and Climate Change Canada, Toronto, Ontario M3H 5T4, Canada.
Leiming
L
Zhang
Key Laboratory for Environmental Pollution Prediction and Control, Gansu Province, College of Earth and Environmental Science, Lanzhou University, Lanzhou 730000, China.
Xiaoxue
X
Liang
Key Laboratory for Environmental Pollution Prediction and Control, Gansu Province, College of Earth and Environmental Science, Lanzhou University, Lanzhou 730000, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China. Electronic address: jianminma@lzu.edu.cn.
Jianmin
J
Ma
Key Laboratory for Environmental Pollution Prediction and Control, Gansu Province, College of Earth and Environmental Science, Lanzhou University, Lanzhou 730000, China.
Hong
H
Gao
Key Laboratory for Environmental Pollution Prediction and Control, Gansu Province, College of Earth and Environmental Science, Lanzhou University, Lanzhou 730000, China.
Tao
T
Huang
Key Laboratory for Environmental Pollution Prediction and Control, Gansu Province, College of Earth and Environmental Science, Lanzhou University, Lanzhou 730000, China.
Kai
K
Zhang
D000336:Aerosols; D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry*; D002617:Chemical Industry; D002681:China; D003889:Desert Climate; D004391:Dust / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods*; D017745:Incineration; D000066388:Oil and Gas Industry; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis* / Q000737:chemistry*; D001335:Vehicle Emissions / Q000032:analysis
D000336:Aerosols; D000393:Air Pollutants; D004391:Dust; D052638:Particulate Matter; D001335:Vehicle Emissions
Aerosol mass closure; Chemical composition; PM(2.5); Source apportionment; Thermodynamic equilibrium model