An assessment of global and regional emissions of trace metals to the atmosphere from anthropogenic sources worldwide

Abstract

An accurate and complete emission inventory for atmospheric trace metals on a global scale is needed for both modeler community and policy makers to assess the current level of environmental contamination by these pollutants, major emission sources and source regions, and the contribution of the atmospheric pathway to the contamination of terrestrial and aquatic environments. Major progress has been made in assessing emissions of trace metals in various countries and even regions, e.g., Europe, since the first global emission estimate for these pollutants was made by Nriagu and Pacyna (1988). These improved national and regional emission inventories have been used in this work to assess the global trace metal emissions from anthropogenic sources in the mid-1990s. The results of this work conclude that stationary fossil fuel combustion continues to be the major source of Cr, Hg, Mn, Sb, Se, Sn, and Tl with respect to the coal combustion and the major source of Ni and V with respect to oil combustion. Combustion of leaded, low-leaded, and unleaded gasoline continues to be the major source of atmospheric Pb emissions. The third major source of trace metals is non-ferrous metal production, which is the largest source of atmospheric As, Cd, Cu, In, and Zn. The largest anthropogenic emissions of atmospheric trace metals were estimated in Asia. This can be explained by growing demands for energy in the region and increasing industrial production. As a result, the Asian emissions are not only larger than the emissions on other continents, but also show an increasing trend. Another factor contributing to high emissions in Asia is the efficiency of emission control, which is lower than in Europe and North America. Concerning the two latter continents, emissions of trace metals show a decreasing tendency over the last two decades. Key words: anthropogenic sources, atmospheric emissions, trace metals, global emission inventory