WASHINGTON – Emissions of sulfur dioxide, which causes acid rain, rose 4 percent in 2003, but probably will not compromise long-term air quality goals, the government reported Wednesday.

Coal-fired power plants were the main source of the 10.6 million tons of sulfur dioxide. That total compared with 10.2 million tons in 2002 and reverted to the level from 2001.

Nonetheless, pollution from sulfur dioxide has dropped significantly over the past two decades, from 17.3 million tons in 1980 to 11.2 million tons in 2000, the year before President Bush took office. The total is within striking distance of lawmakers’ goal of cutting such emissions to 8.95 million tons by 2010 – about half of the amount from 1980.

The Environmental Protection Agency released the information as part of an annual report required by Congress.