Improvements to the Accuracy of Atmospheric Oxidized Mercury Measurements
Improvements to the Accuracy of Atmospheric Oxidized Mercury Measurements
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DOI：
10.1021/acs.est.0c02747
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发表时间：
2020-11-03
影响因子：
11.4
通讯作者：
Luippold, Adriel
中科院分区：
文献类型：
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作者：
Lyman, Seth N.;Gratz, Lynne E.;Luippold, Adriel
我们开发了一种基于阳离子交换膜的双通道系统来测量元素汞和氧化汞，并于 2018 年夏季将其与自动校准系统和内华达大学雷诺反应汞活性系统 (UNR-RMAS) 一起部署在科罗拉多州的农村/郊区现场。与通过广泛使用的 KCl 去除器方法收集的氧化汞测量值不同，双通道系统能够定量回收通过注入的 HgCl2 和 HgBr2。将校准器放入环境空气样本中，并与 UNR-RMAS 测量结果进行比较。该系统每隔 10 分钟进行一次测量，氧化汞的 3 小时平均检测限为 33 pg m(-3)。它能够检测氧化汞（0 至 200 pg m-3）的日常变化和昼夜循环，并将成为未来大气汞研究的重要工具。我们使用重量分析法独立测定渗透管的总汞渗透率。当汞渗透率相对较高（高达 30 pg s(-1)）时，重量法得出的渗透率与通过汞测量装置观察到的渗透率相匹配，误差在 25% 以内，但渗透率较低时，一致性会降低，这可能是因为重量分析的不确定性增加。
We developed a cation-exchange membrane-based dual-channel system to measure elemental and oxidized mercury and deployed it with an automated calibration system and the University of Nevada, Reno-Reactive Mercury Active System (UNR-RMAS) at a rural/suburban field site in Colorado during the summer of 2018. Unlike oxidized mercury measurements collected via the widely used KCl denuder method, the dual-channel system was able to quantitatively recover HgCl2 and HgBr2 injected by the calibrator into the ambient sample air and compared well with the UNR-RMAS measurements. The system measured at 10 min intervals and had a 3-h average detection limit for oxidized mercury of 33 pg m(-3). It was able to detect day-to-day variability and diel cycles in oxidized mercury (0 to 200 pg m-3) and will be an important tool for future studies of atmospheric mercury. We used a gravimetric method to independently determine the total mercury permeation rate from the permeation tubes. Permeation rates derived from the gravimetric method matched the permeation rates observed via mercury measurement devices to within 25% when the mercury permeation rate was relatively high (up to 30 pg s(-1)), but the agreement decreased for lower permeation rates, probably because of increased uncertainty in the gravimetric measurements.