|Abstract Title:||Use of the passive sampler (MerPAS) to quantify the concentration and isotope composition of atmospheric gaseous mercury in China|
|Presenter Name:||Xiaomiao Mu|
|Company/Institution:||Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China|
|Session:||Mercury Emissions: Monitoring and Analysis|
|Co-Authors:||Xiaomiao Mu,Ruoyu Sun|
Abstract Information :
Mercury (Hg) is a toxic metal with biological toxicity and high volatility. It mainly exists as gaseous elemental mercury Hg(0) and has a long residence time in the air, enabling its global dispersion. Multi-scale monitoring of atmospheric Hg concentration is key for evaluating the implementation effectiveness of the Minamata Convention. Because the passive sampler has the advantages of simple operation, no need for energy supply, and resistance to the harsh environment, it is a useful supplement to the existing active sampling technology for atmospheric Hg(0) monitoring. Recent studies have shown that the atmospheric Hg(0) collected by the passive sampler (MerPAS) can be applied to the analysis of concentration and stable mercury isotope composition at the same time. Unlike the active samplers which could quantitatively collect atmospheric gaseous mercury and retain its isotope composition. The atmospheric gaseous mercury captured by MerPAS adsorbent is not quantitative, possibly causing a large isotope offset between the real and captured atmospheric gaseous mercury. Although this offest has been proved to be relatively constant under prescribed environment parameters, its controlling factors are still unknown, limiting the wide application of MerPAS. Here, we deployed MerPAS and active samplers at the same sites (urban site of Tianjin, and background site of Tibet Plateau) for atmospheric gaseous mercury collection in China. Our results show that MerPAS could accurately monitor the atmospheric Hg concentrations, and conserve the mass-independent fractionation signatures (?xxxHg) of atmospheric Hg(0). The offset of mass-dependent fractionation signatures (ë202Hg) between the real and captured atmospheric gaseous mercury was mostly constant and comparable to previously reported values. The atmospheric gaseous mercury in the urban site of Tianjin was characterized by negative ë202Hg and near-zero ?xxxHg, which are significantly different from the positive ë202Hg and small negative ?xxxHg of atmospheric gaseous mercury at the background site of Tibet Plateau.