Two-year monitoring of gaseous elementary mercury in a typical iron-steel plant in Yangtze River Delta, China: Characterization and estimation of its dynamic oxidation

Deming Han; Qingyan Fu; Song Gao; Zihao Hu; Xufeng Zhang; Xiaolin Chen; Jingjing Feng; Jinping Cheng; Wenhua Wang

doi:10.1016/j.scitotenv.2018.12.133

Two-year monitoring of gaseous elementary mercury in a typical iron-steel plant in Yangtze River Delta, China: Characterization and estimation of its dynamic oxidation

Sci Total Environ. 2019 Mar 20:657:1217-1226. doi: 10.1016/j.scitotenv.2018.12.133. Epub 2018 Dec 11.

Authors

Deming Han¹, Qingyan Fu², Song Gao³, Zihao Hu⁴, Xufeng Zhang¹, Xiaolin Chen¹, Jingjing Feng¹, Jinping Cheng⁵, Wenhua Wang¹

Affiliations

¹ School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
² Shanghai Environmental Monitor Center, Shanghai 200235, China.
³ Shanghai Environmental Monitor Center, Shanghai 200235, China; Department of Environmental Science and Engineering, Fudan University, Shanghai 200433, China.
⁴ School of Chemistry and Chemical Engineering, Hefei University of Technology, Hefei 230009, China.
⁵ School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: jpcheng@sjtu.edu.cn.

PMID: 30677888
DOI: 10.1016/j.scitotenv.2018.12.133

Abstract

A two-year gaseous elementary mercury (GEM) measurement was implemented at an iron-steel plant in Yangtze River Delta, China, which provided an excellent opportunity to investigate their dynamic cycling. The hourly GEM concentrations ranged between 0.78 and 113.8 ng m^-3, with a mean value of 3.83 ± 2.53 ng m^-3. Temporally, seasonal GEM contents decreased as winter ≈ spring > summer > autumn, while diurnal cycling was observed with a steady decrease at 14:00-17:00. GEM variations were found to be related to source emissions, meteorology and regional transportation. Three major oxidants (O₃, Br and OH radicals) were used to evaluate GEM oxidation in the daytime, and the estimated GEM depletion rate was 70.8 ± 52.5 molecule cm^-3 s^-1 (0.09 ± 0.06 ng m^-3 h^-1). The GEM oxidized by Br radicals accounted for 83.4% of the total GEM oxidation rate, followed by O₃ (13.8%). The estimated atmospheric lifetime of GEM was 22.9 to 345.2 days, which implies a major contribution of Br radicals to the GEM sink. These findings highlight the ability of iron-steel industry emissions and in-situ oxidation to affect daily local GEM cycling significantly.

Keywords: Dynamic oxidation; Iron–steel; Mercury; Photochemical; Yangtze River Delta.