Aerosol pollution in a megacity of southwest China inferred from variation characteristics of sulfate-δ34S and water-soluble inorganic compositions in TSP--颗粒学报PARTICUOLOGY

Zhou, Y., Xiaodong, L., Shilu, W., Qinkai, L., Jun, H., & Gaoyang, C. (2019). Aerosol pollution in a megacity of southwest China inferred from variation characteristics of sulfate-δ34S and water-soluble inorganic compositions in TSP. Particuology, 43, 202-209. https://doi.org/10.1016/j.partic.2018.03.009

Aerosol pollution in a megacity of southwest China inferred from variation characteristics of sulfate-δ³⁴S and water-soluble inorganic compositions in TSP

Zhou Yang ^a, Xiaodong Li ^b *, Shilu Wang ^c, Qinkai Li ^b, Jun Huang ^c, Gaoyang Cui ^c

a Department of Tourism and Geography, Tongren University, Tongren 554300, China
b Institute of Surface-Earth System Sciences, Tianjin University, Tianjin 300072, China
c State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guizhou 550081, China

10.1016/j.partic.2018.03.009

Volume 43, April 2019, Pages 202-209

Received 15 August 2017, Revised 9 February 2018, Accepted 2 March 2018, Available online 20 August 2018, Version of Record 19 February 2019.

E-mail: xiaodong.li@tju.edu.cn

Highlights

• Daytime and nighttime aerosol samples for total suspended particles (TSP) were collected in Chengdu.

• Mean mass concentrations of TSP in winter (643 μg/m³) were higher than those in summer (160 μg/m³).

• SO₄²⁻, NO₃⁻, NH₄⁺ during misty days were 2–5 times higher than those of other weather conditions.

• Coal combustion and vehicle exhaust would likely be the major sources of sulfate in TSP in Chengdu.

Abstract

Daytime and nighttime aerosol samples for total suspended particles (TSP) were collected in Chengdu from 12 to 23 January 2013 (winter) and 10 to 21 August 2014 (summer). The mass concentrations of TSP, major inorganic ions, and stable sulfur isotope ratios were determined. Clear winter–summer variation in TSP was observed; the mass concentrations of TSP in summer were below levels defined by the Chinese National Ambient Air Quality Standard (GB3095-2012), whereas winter TSP levels exceeded the standard by 2–4 times. Overall, the sum of SO₄²⁻, NO₃⁻, and NH₄⁺ concentrations represented the highest contribution to water-soluble ionic components, which showed similar trends to TSP mass. According to correlations among major ions, the major compounds in TSP were likely to be (NH₄)₂SO₄, NH₄NO₃, CaCl₂, and KCl in both sampling times, and CaSO₄ and Ca(NO₃)₂ were also present in summer. The NO₃⁻/SO₄²⁻ ratios ranged from 0.57 to 1.28 (average 0.85 ± 0.16) in winter and 0.5 to 0.93 (average 0.66 ± 0.11) in summer, indicating stationary source emissions (coal burning) were more important sources than the vehicle exhaust. The relationship between SO₄²⁻ and δ³⁴S indicated the sulfate sources were affected by the low sulfur isotope value of biogenic sulfur release in summer, and the high sulfur isotope value of coal in winter. As a whole, the mixture of coal burning and vehicle exhaust represent the major TSP sources in Chengdu in the study period, and biogenic sulfur also contributes to TSP in summer.

Graphical abstract

Keywords

Aerosol pollution; Variation characteristics; Sulfate-δ³⁴S; Total suspended particle

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