The mercury (Hg) research community is in need of a method to quantify reactive, gaseous oxidized, and particulate-bound Hg compounds. The University of Nevada, Reno-Reactive Mercury Active System (UNRRMAS) was designed to quantify reactive Hg, as well as identify compounds present in the atmosphere. This system has undergone significant improvements and is now designated as UNR-RMAS 2.0. The system physical design, flow management, and sample analytical methods have been improved. A new sample manifold increased reliability and consistency of air flow. The thermal desorption method for identification of gaseous oxidized Hg compounds was improved with respect to temporal resolution and temperature management. A statistical method was developed that allows for quantifying reactive Hg (RM) compounds. In addition, analyses of anions on nylon membranes was investigated as means of understanding air mass chemistry and potential RM compounds. The results of these improvements are demonstrated through comparison of a year of UNR-RMAS 2.0 sample data collected in 2018–2019 with that collected in 2014–2015. Implemented changes resulted in improved sample replication and resolution of RM quantification and speciation.

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