Accurately measuring reactive gaseous mercury (RGM) concentrations in the atmosphere is important to improve our understanding of the global mercury (Hg) cycle. In this study, we compared the RGM collection efficiencies of four sampling methods, including a 14 cm long KCl-coated denuder, a KCl-coated glass fiber filter, a KCl-coated quartz sand tube, and a cation exchange membrane. Both laboratory studies and field RGM monitoring were performed in environments with low humidity [relative humidity (RH) of ∼20%], medium humidity (RH of 50–70%), and high humidity (RH of ∼100%). Laboratory results showed that in environments with <70% RH, RGM amounts collected by the KCl-coated glass fiber filter and the KCl-coated quartz sand tube were comparable with those collected with the cation exchange membrane. In environments with ∼100% RH, the cation exchange membrane collected more RGM, approximately 1.1–1.4, 1.1–1.2, and 2.4–2.7 times more than the KCl-coated glass fiber filter, KCl-coated quartz sand tube, and KCl-coated denuder, respectively. During field monitoring, RGM amounts collected with the KCl-coated quartz sand tube were comparable to those collected with the cation exchange membrane regardless of the RH in the environment (p > 0.05; n = 60). Large variations (≤20 during field monitoring) in RGM concentrations measured by different sampling methods indicate the need for a unified and standardized method for future RGM monitoring.

中文翻译：

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在实验室测试和现场监测中采用不同采样方法收集反应性气态汞的比较

准确测量大气中的反应性气态汞（RGM）浓度对于增进我们对全球汞（Hg）循环的理解非常重要。在这项研究中，我们比较了四种采样方法的RGM收集效率，包括14 cm长的KCl涂层的剥蚀仪，KCl的玻璃纤维滤池，KCl的石英砂管和阳离子交换膜。实验室研究和现场RGM监测均在低湿度[相对湿度（RH）约为20％]，中等湿度（RH为50–70％）和高湿度（RH约为100％）的环境中进行。实验室结果表明，在相对湿度小于70％的环境中，用KCl涂层的玻璃纤维过滤器和KCl涂层的石英砂管收集的RGM量与用阳离子交换膜收集的RGM量相当。在相对湿度约为100％的环境中，阳离子交换膜收集到的RGM分别比使用KCl涂层的玻璃纤维滤池，使用KCl涂层的石英砂管和使用KCl涂层的剥蚀器多出约1.1-1.4、1.1-1.2和2.4-2.7倍。在现场监测期间，无论环境中的相对湿度如何，用KCl涂层石英砂管收集的RGM量与用阳离子交换膜收集的RGM量是可比的（p > 0.05；n = 60）。通过不同的采样方法测得的RGM浓度变化很大（在现场监测中≤20），这表明需要采用统一和标准化的方法来进行将来的RGM监测。