Trends in emissions of acidifying species in Asia, 1985-1997

Acid deposition is a serious problem throughout much of Asia. Emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) have been increasing steadil y, as nations strive to increase their levels of economic development. Coal and fuel oil have been the main choices for powering industrial developmen t; and, until recently, only a few countries had taken steps to avert the a tmospheric emissions that accompany fuel combustion. This paper discusses t rends in emissions of SO2 and NOx that have occurred in Asian countries in the period 1985-1997, using results from the RAINS-Asia computer model and energy-use trends from the IEA Energy Statistics and Balances database. Emi ssions of SO2 in Asia grew from 26.6 Tg in 1985 to 33.7 Tg in 1990 and 39.2 Tg in 1997. Though SO2 emissions used to grow as fast as fossil-fuel use, recent limitations on the sulfur content of coal and oil have slowed the gr owth. The annual-average emissions growth between 1990 and 1997 was only 2. 2%, considerably less than the economic growth rate. Emissions of NOx, on t he other hand, continue to grow rapidly, from 14.1 Tg in 1985 to 18.7 Tg in 1990 and 28.5 Tg in 1997 (6.2% per year between 1990 and 1997), with no si gns of abating. Thus, though SO2 remains the major contributor to acidifyin g emissions in Asia, the role of NOx will become more and more important in the future.