The tropospheric burden of arsenic has been estimated from representative global surface concentrations and an estimated small particle tropospheric scale height of 3.9 km to be ~8¿108 g As. Total atmospheric arsenic emissions from both natural and anthropogenic sources have been estimated to be 31¿109 g As/yr. On a global bais the major source of atmospheric arsenic appears to be from anthropogenic volatilization processes, and the major natural sources of arsenic appear to be volcanoes and the terrestrial biosphere. Total atmospheric arsenic removal is estimated to be 30--50¿109 g As/yr. The global tropospheric residence time of arsenic appears to be about 9 days.