Although short-lived in the atmosphere, aerosols have the theoretical possibility to cool the atmosphere and are sometimes referred to as 'anti-greenhouse gas. Estimates of both their magnitude and importance vary from a relatively small influence to one which, in the Northern Hemisphere, can counter the entire greenhouse forcing up to the present.

One of the first steps in considering the impact of anthropogenic sulfates is the development of an accurate regional emission inventory of sulfur as a function of time. There have been several attempts to identify trends of sulfur dioxide emissions for the period since the middle 1800s. Large discrepancies among the approximations reflect the many uncertainties associated with estimating the sulfur estimates. Besides global determinations, continental or national estimates of sulfur emissions have been made.

Beginning in September 1994, under a grant from the U.S. Department of Energy, A.S.L. & Associates and its subcontractor, CAPITA at Washington University St. Louis, and consultant Dr. Peter Brimblecombe combined talents to develop a database that allows for the estimation of the global emissions of sulfur from 1850 to 1990. A common methodology was applied across all years and countries for the estimation of sulfur emissions. In all cases, the emission estimates for each country are based on the production, percent sulfur, and sulfur retention information associated with that country's activities. If data were available, such as United States emission estimates from the U.S. Environmental Protection Agency, the information was used only for purposes of comparison with the estimate results derived from this research effort.

Temporal resolution information is available from the database; thus, changes associated with specific historical events (e.g., wars, internal reorganizations, etc.) are clearly observed in the emissions inventory on a national, regional, or global basis. Some of the important uses of ASL/CAPITA global sulfur emission inventory are to serve as (1) input into global pollution models; (2) a way to compare the global sulfur emission patterns to atmospheric sulfur concentration data; and (3) the basis for global sulfur emission projections. This research effort attempts to correct some of the deficiencies associated with previous global sulfur emissions by (1) identifying those production activities that resulted in sulfur emissions by country and (2) calculating historical emission trends by country across years. Emission estimates derived from this research effort have been compared with previous estimates to put into perspective how well the sulfur estimates in the ASL/CAPITA data based for each country compared with the previously used methods. Our estimate for global sulfur emissions from 1850 to 1990 is available.

The database is available. We suggest that you order the A.S.L. & Associates report from the National Technical Information Service (NTIS) of the U.S. Department of Commerce. The report provides the detailed information on how the database was created. To purchase a copy of the peer-reviewed U.S. Department of Energy Report, please refer to it as NTIS Order Number DE96014790INZ. The NTIS sales desk staff is available between 0830 and 1700, U.S. eastern time at 703-487-4650. The mailing address is NTIS, 5285 Port Royal Road, Springfield, VA 22161. Fax orders can be made at 703-321-8547. To verify receipt of a fax, please call 703-487-4679. The database can be accessed. Please note that a paper appeared describing our research effort and summarizing our findings in the peer-reviewed journal, Atmospheric Environment. The citation for this paper can be found in our publication section.