The Causes and Effects of Acid Rain

One of the many phrases thrown around in environmental circles is “acid rain”. Acid rain seems to be responsible for everything from the death thousands of acres of forest to the birth of a baby with a unibrow. It’s been a major focus of green movements for the past twenty years. You can probably deduce that acid rain is basically acidic water, but where does the acid come from? And what are the real effects of acid rain?

The major cause of acid rain is fossil fuel combustion. When we burn coal, gas, and other fuel, sulfur dioxide and nitrogen oxides escape into the atmosphere. These gases react with molecules in the air to form sulfuric and nitric acid, which then precipitate into acid rain.

The problem is that the free gases are particularly mobile. Winds can drive them hundreds of miles from their points of origin- meaning that chemicals emitted in an industrial park can travel to a distant nature park.

While acid rain may not cause unibrows, it can have severe, negative effects on trees and soils. When acid rain hits leaves and needles, it damages their surfaces. This impairs trees’ ability to reproduce and to withstand cold. When it soaks into soil, acid rain can deplete essential nutrients, weakening the soil’s ability to support plant life.

Acid rain also causes problems in rivers and lakes. Most aquatic animals can only live within a narrow pH range; if the water turns too acidic, they die. In the Adirondack Mountains in upstate New York, for example, acid rain has severely depleted brook trout populations.

In addition, some scientists suspect that acid rain might affect human health. The gases that form acids carry small particles and periodically release them into the atmosphere. Inhaling these particles can cause serious respiratory problems. Less importantly, acid rain can damage buildings, statues, and monuments. Calcium compounds in limestone, sandstone, marble and granite bond with acid to create gypsum, which wears away easily.

So can we do anything? Over time, acids in soils and rivers will leach out. But the leaching will have no effect if we don’t reduce sulfur and nitrogen emissions. And the best way to reduce emissions is by using less gas. So bike to work occasionally instead of driving, take mass transit to get around, and turn on your air conditioning and heating less often. Even for a problem as big as acid rain, small steps can make a difference.

http://www.epa.gov/region1/eco/acidrain/intro.html

http://www.ec.gc.ca/acidrain/acidforest.html

http://environment.nationalgeographic.com/environment/global-warming/acid-rain-overview.html