idic in character, and, if the precipitation is rain, it is acid rain. This contaminated fallout from clouds may be hundreds of miles distant from the original sources of the air pollution. Thus, the acid rain that falls in Ontario may result from pollution introduced in Illinois through public utility company operations or it may result from burning at waste disposal facilities located virtually next door.
Sulfur dioxide produced through the burning of fossil fuels is oxidized in the atmosphere and becomes sulfur trioxide. The sulfur trioxide dissolves in the water in clouds, forming an acid solution that eventually falls to the earth from the clouds.
A substantial amount of sulfate in solution exists in the sea. This sulfate is synthesized into organic sulfur compounds by marine plants, and is released by these plants as dimethyl sulfide from the sea to the atmosphere. In the atmosphere, the dimethyl sulfide is oxidized into sulfuric acid, which, in turn, causes rain to become acid in character.
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