It's the acid rain that erodes granite and concrete buildings because there's a chemical reaction. It's acid rain that erodes steel bridges, so they have to be replaced. So there's a real dollar cost associated with it in terms of the things that human beings have built in the past. The sulfur dioxide is a byproduct of burning coal for electrical power. That causes a particular problem for us here in Maine, Hamilton says.
Maine is downwind of all of the electric power plants in the United States.
The prevailing winds are vaguely Northeast. Maine has acid rain. The pH of precipitation recorded by the Maine Department of Environmental Protection in November 1995 was 3.9 at Acadia National Park, 3.9 at Bridgeton and 4.25 at Greenville. Hamilton says rain is considered abnormally acidic when it's pH is below 5.0. Lakes are considered acidic when pH falls below 5.5.