Comparative analysis of reactive mercury measurement methodology and environmental correlates in Australia

Accurate quantification of atmospheric mercury (Hg) is critical for understanding the Hg biogeochemical cycle and for the development of effective policy and management. However, measurement uncertainties as well as oxidation chemistry and other environmental influences make accurate quantification difficult. A method comparison between the Tekran speciation system (2537/1130/1135) and the University of Nevada Reno Reactive Mercury Active System (UNRRMAS) is provided for the first time within the Sydney urban environment, which ran for a total of 9 months. It was found that GOM collected by the Tekran speciation system and RM by the CEMs within the UNRRMAS collected mean concentrations of 18.21 ± 10.56 pg m-3 and 14.57 ± 5.45 pg m-3, respectively. These methods were found to be comparable during the study. An investigation into a number of environmental parameters at the MQ AWS site found there to be no observed relationship with O3 chemistry or other environmental parameters under linear regression analysis, suggesting that they exert little influence on RM concentrations. However, it is suggested that synoptic and mesoscale circulation patterns may play a key role in the concentration and dispersal of RM at the site, which is thought to be due to the unique topographical and climatological characteristics of the Sydney Basin.