Source: R. Downing, R. Ramankutty, and J. Shah, RINS-ASIA: An Assessment Model for Acid Deposition in Asia (The World Bank, Washington, D.C., 1997), p. 11.

The graph above shows SO₂ emissions coming from each continent.  Total emissions are given in millions of metric tons.

Emissions for Africa, despite the fact that the region is large and highly populated, are very low.  This can be attributed to the continent's low economic development.

It appears that emissions from North America and Europe, the most developed regions of the world, are finally beginning to decrease.  Environmental activism and responsive government action are probably among the leading causes for this effect.

Asia, by contrast, has recently seen a heavy increase in SO₂ emissions.  Rapid economic growth and industrialization in China is the primary cause of this.  While China's economy has boomed, this has been at the cost of severe degradation of the environment.