Equation of sulfurous acid to sulfuric acid?
2H2SO3 + O2 -----> 2H2SO4
The most important sources of acids in acid rain are mostly combustion fuels, including coal, gasoline, fuel oils, and so on. These have impurities that produce sulfuric and sulfurous acids. They also convert atmospheric nitrogen into acids. The most important natural source of acid in acid rain is volcanoes, which produce sulfuric and sulfurous acids.