Chemical composition and source apportionment of the ambient PM2.5 in Hangzhou, China--颗粒学报PARTICUOLOGY

Liu, G., Li, J., Wu, D., & Xu, H. (2015). Chemical composition and source apportionment of the ambient PM2.5 in Hangzhou, China. Particuology, 18, 135–143. https://doi.org/10.1016/j.partic.2014.03.011

Chemical composition and source apportionment of the ambient PM_2.5 in Hangzhou, China

Gang Liu^*, Jiuhai Li, Dan Wu, Hui Xu

School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China

10.1016/j.partic.2014.03.011

Volume 18, February 2015, Pages 135-143

Received 20 December 2013, Revised 3 March 2014, Accepted 5 March 2014, Available online 23 June 2014.

E-mail: liugang650104@sina.com

Highlights

• PM_2.5 pollution was investigated in Hangzhou, China during April 2004 to March 2005.

• Water-soluble ions, metal elements, and total carbon in PM_2.5 were determined.

• Temporal and spatial distributions for PM_2.5 and its components were studied.

• Emission sources of PM_2.5 in the central area were identified using positive matrix factorization.

Abstract

To identify and apportion the sources of the ambient PM_2.5 in the urban area of Hangzhou, China, PM_2.5 samples were collected at three sites in the city from April 2004 to March 2005. Water-soluble ions, metal elements, and total carbon (TC) in PM_2.5 samples were analyzed. The results indicated that the 24-h mean concentrations of PM_2.5 ranged from 17.1 to 267.0 μg/m³, with an annual average value of 108.2 μg/m³. Moreover, the seasonal mean values for PM_2.5 in spring, summer, autumn, and winter were 116, 73.1, 114.2, and 136.0 μg/m³, respectively. According to the Chinese ambient quality standard, at least 70% of the monitoring data exceeded the limit value. The total contribution of water-soluble ions, including F⁻, Cl⁻, NO₃⁻, SO₄²⁻, NH₄⁺, K⁺, and Na⁺, to PM_2.5 mass varied from 32.3% to 36.7%. SO₄²⁻, NO₃⁻, and NH₄⁺ were the main constituents of the ions, with contributions to PM_2.5 varying from 14.1% to 14.7%, 6.0% to 7.8%, and 6.4% to 7.7%, respectively. In addition, the annual mean mass fraction of TC in PM_2.5 was 27.8%. The annual average total contribution of the group of elements of Zn, Pb, Cu, Mn, Cr, Ni, Se, Mo, Cd, Sb, and Ag to the aerosol was in the range of 1.7–2.0%. Furthermore, positive matrix factorization was applied to analyze the PM_2.5 data collected from the central area, and five factors were identified. The factor contributions to PM_2.5 mass were 12.8%, 31.9%, 10.1%, 17.2%, and 27.9%, respectively. Iron/steel manufacturing and secondary aerosol were the main sources for the fine particles. These findings may have significance for controlling the atmospheric contamination in the city.

Graphical abstract

Keywords

PM_2.5; Water-soluble ion; Metal element; TC; Source apportionment; Chemical composition

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