Mercury-in the chemical/physical forms present in the biosphere-is a persistent, toxic, bioaccumulative pollutant that is dispersed throughout the environment on a global scale, mainly via the atmosphere. It is among the heavy metals for which the natural biogeochemical cycle has been perturbed by a wide range of human activities, including fossil-fuel combustion and waste incineration. Results of our recent measurements of gaseous elemental mercury (GEM), as well as total particulate-phase mercury (TPM) concentrations in Arctic air, 'total Hg' concentrations in Arctic snow, and tropospheric BrO concentrations from an earth-orbiting-satellite platform are presented and discussed. Findings of our research, and the conclusions derived therefrom, are important for environmental protection as well as the health and well-being of aboriginal people in Arctic circumpolar nations. ¿ 2001 American Geophysical Union