An examination of the major anthropogenic and natural sources of atmospheric selenium indicates that approximately 13--19¿109 g Se are cycled through the troposphere annually. Perhaps 60% of this flux is natural in origin, and both man-made and biological emission appear to be predominantly gaseous in nature. Emission from the marine biosphere and the combustion of coal account for 50--65% of the total atmsopheric selenium emissions, and the natural marine flux appears to be roughly twice as large as that due to coal combustion. ¿ American Geophysical Union 1987