image- Trees damaged by acid rain

Click on the arrows below to view the answers

What causes acid rain?

blue arrow

What does acid rain consist of?

green arrow

What are two harmful effects of acid rain?

purple arrow

Listen to an audio clip on this subject.

Download audio file  Download mp3 file
.wav or .mp3

download time over 28.8 modem
3 minutes



Research funded by NSF that identified acid rain and its effects conducted at the Hubbard Brook Experimental Forest in NH, began in the early 1960s, with major research findings presented in 1972.

NSF began funding Long-term ecological research (LTER) at Hubbard Brook Experimental Forest in 1987. This long-term research led to important changes in the 1990 amendments to the Clean Air Act. Hubbard Brook Experimental Forest receives nearly all of its funding from NSF.

Acid rain is caused primarily fromthe burning of high-sulfur coal and oil used to fuel electric power plants. Emissions from these sources are transported through the atmosphere and are deposited on locations downwind through rain, snow, sleet, hail and via dry deposition of acidifying gases and particles and cloud and fog water.

These are important sources of acid rain. Considered a widespread, regional phenomenon in eastern North America, the Scandinavian countries and elsewhere throughout the world, acid rain consists of abnormally high acidic levels in rain, snow, fog and cloud water.

While the long-term effects of acid rain are still being studied, it is well documented that effects include harm to freshwater ecosystems and widespread decline in forest health,including damage to more than 70 percent of the red spruce forests in parts of New England.

Return to top