Seasonal and Annual Variations in Atmospheric Hg and Pb Isotopes in Xi'an, China
Seasonal and Annual Variations in Atmospheric Hg and Pb Isotopes in Xi'an, China
复制标题
中国西安市大气汞、铅同位素的季节和年变化
DOI：
10.1021/acs.est.6b06145
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发表时间：
2017
影响因子：
11.4
通讯作者：
Junji Cao
中科院分区：
文献类型：
--
作者：
Hongmei Xu;Jeroen E. Sonke;Benjamin Guinot;Xuewu Fu;Ruoyu Sun;Aurelie Lanzanova;Frederic C;audap;Zhenxing Shen;Junji Cao
本文报道了西安市3年时间序列中总悬浮颗粒物（TSP）和总气态汞（TGM）的铅（Pb）和汞（Hg）浓度和同位素特征。TSP（299±120 μg m-3）、PbTSP（0.33±0.15 μg m-3）、HgTSP（0.64±0.54 ng m-3）和TGM（5.7±2.7 ng m-3）的平均浓度升高。我们发现，自2003年以来，西安冬季大气中的铅水平每年下降4.6%，但相对于空气质量标准仍处于较高水平，因此是一个主要的健康问题。δ202HgTGMand分别为Δ199HgTSPaveraged - 0.80±0.30‰（1σ）和- 0.02±0.10‰（1σ）， δ202HgTGMand分别为Δ199HgTGMaveraged - 0.08±0.41‰（1σ）和0.00±0.04‰（1σ）。相对于陕西及周边省份原煤，δ202HgTGMis富集轻汞同位素，δ202HgTGMis富集重汞同位素。TSP和TGM Δ199Hg特征与原煤难以区分，表明在近场城市-工业环境中大气Hg的光化学质量无关分异作用很小。δ 202hgtgm与TGM水平显著相关（r2= 0.3,p< 0.01），可能反映了当地工业TGM排放与全球背景TGM的二元混合。
We present a 3-year time series of lead (Pb) and mercury (Hg) concentrations and isotope signatures in total suspended particulate (TSP) matter and as total gaseous Hg (TGM) in Xi’an, Northwestern China. Mean concentrations of TSP (299 ± 120 μg m–3), PbTSP(0.33 ± 0.15 μg m–3) and HgTSP(0.64 ± 0.54 ng m–3), and TGM (5.7 ± 2.7 ng m–3) were elevated. We find that atmospheric Pb levels in winter in Xi’an have decreased by 4.6% per year since 2003, yet remain elevated relative to air quality guidelines and therefore a major health concern. δ202HgTSPand Δ199HgTSPaveraged −0.80 ± 0.30‰ (1σ) and −0.02 ± 0.10‰ (1σ) and δ202HgTGMand Δ199HgTGMaveraged −0.08 ± 0.41‰ (1σ) and 0.00 ± 0.04‰ (1σ). Relative to raw coal from Shaanxi and surrounding provinces, δ202HgTSPis enriched in the light Hg isotopes, whereas δ202HgTGMis enriched in the heavy isotopes. TSP and TGM Δ199Hg signatures are indistinguishable from raw coal, indicating little photochemical mass independent fractionation of atmospheric Hg in the near-field urban-industrial environment. δ202HgTGMcorrelates significantly with TGM levels (r2= 0.3,p< 0.01) and likely reflects binary mixing of local industrial TGM emissions with global background TGM.