EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Hourly resolution measurement of gaseous oxidized mercury using a membrane-coupled sampling system 

Qingru Wu, Yi Tang, Shuxiao Wang, Guoliang Li, Deming Han, Kaiyun Liu, and Zhijian Li
Qingru Wu et al.
  • State Key Joint Laboratory of Environmental Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China

Temporal variation trend of gaseous oxidized mercury (Hg2+) in air is significant to understand global mercury cycling and is urgent to evaluate the effectiveness of the Minamata Convention on Mercury. However, Hg2+ monitoring is still one of the largest challenges in atmospheric mercury research field, where existing methods cannot simultaneously satisfy the measurement requirements of both accuracy and time precision. Here, we developed a hourly resolution gaseous oxidized mercury sampling system (HGOMS) which coupled a cation exchange membrane (CEM)-based sampling system with the Tekran 2537/1130/1135 equipment. The two stage CEM coupled in our system can capture almost all Hg2+ under high HgBr2 exposure (1.45±0.05 ng m-3) in laboratory experiment. During the field observation, the breakthrough percentage of the first stage is approximately 10% and the time resolution of Hg2+ concentration measurement is 2 h. The 3-week measurement using HGOMS showed an hour-average Hg2+ concentration of 0.46±0.36 ng m-3, which is approximately 23 times higher than the measurement using KCl-coated denuder at urban Beijing. In addition, enhanced Hg2+ concentrations was observed during the daytime with diurnal amplitude of 0.37 ng m-3, indicating the strong photochemical production of Hg2+. Given the current prevalent low bias of Hg2+ in observation and model simulation, our study indicates the urgency to re-evaluate global Hg2+ measurement and air mercury reaction mechanism in the atmospheric mercury transport model.  

How to cite: Wu, Q., Tang, Y., Wang, S., Li, G., Han, D., Liu, K., and Li, Z.: Hourly resolution measurement of gaseous oxidized mercury using a membrane-coupled sampling system , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4060,, 2022.