By passing the Clean Air Act, Congress expressed the national desire to preserve the ability to see long distances, entire panoramas and specific features in Class 1 Areas such as North Cascades National Park. Since 1980, North Cascades National Park has cooperated with the U.S. Geological Survey, several universities, industry and other agencies to monitor air quality and its impacts. The data help researchers to better understand how pollutants affect park resources. Fish , especially salmonids, are sensitive to increased acid levels in lakes. Acid from polluted rain may impair spawning and reduce young fishes' chances for survival.
Plankton are widely dispersed organisms at the bottom of the food chain.
They are extremely sensitive to minor changes in acidification and thus are good indicators of ecosystem health. Damage to plankton populations may lead to widespread injury to animals at higher levels of the food chain, such as fish and amphibians. Lichens absorb nutrients directly from the atmosphere and have no protective barrier. They accumulate elements and are long-lived, which makes them excellent monitoring species. Plants can be damaged by acid rain and other pollutants, which weaken the plants' ability to withstand disease and insect infestations.