As the century draws to its close, the dark reaches of the world have shifted from the West to the East.
An ambitious analysis of global sulfur emissions estimates spanning two centuries shows that the United States, Europe and the former Soviet Union have stabilized their emissions over the past 20 years, while mainland China's sulfur emissions have soared. China now leads the world in the dubious distinction of most sulfur emissions produced in a country.
Coal consumption overwhelmingly accounted for the highest contributions to sulfur emissions worldwide. Other activities taken into account in the analysis were metal smelting and oil consumption.
The data were gathered and analyzed by Rudolf B. Husar, Ph.D., professor of mechanical engineering and director of the Center for Air Pollution Impact, Trends and Analysis (CAPITA), the world's largest private library of air pollution statistics, at Washington University in St. Louis. He published the analysis in the 1999 fall issue of Atmospheric Environment. Co-authors are Janja D. Husar, Ph.D., research associate in CAPITA, and Allen S. Lefohn, Ph.D., of A.S.L. and Associates in Helena, Mont. The Department of Energy funded part of the research.
"Fuel consumption is the key piece of data," Husar says. "And it is relatively easy to get because most countries have kept track of their consumption." Husar and his colleagues relied on a vast network to get their fuel and metal smelting data. Nineteenth-century data were found in literature and in occasional obscure publications. The 20th- century data were mostly based on League of Nations -- later United Nations -- publications, mineral yearbooks of the U.S. Bureau of Mines, and Her Majesty's Stationary Office in London. The researchers also used fuel consumption data from 1950 to 1990, which previously had been compiled by the U.S. Department of Energy, Oak Ridge National Laboratory. In all, estimates were derived for 234 countries.