Rain, snow, hail, fog and other precipitation wash this solution down to earth as acid rain. Acids can also be transformed chemically into sulphur dioxide gas or sulphur and nitrogen salts that are deposited dry in dust or other particles. Acid rain can affect virtually anything it contacts including soil, water, plants and building materials. In North America, most acid rain falls on the eastern part of the continent, because most acidic air pollutants are produced there, and winds tend to blow toward the east. Despite this progress, however, the recovery of natural ecosystems has been much slower than anticipated.
Acid rain continues to affect our lakes, forests, wildlife and even our health.
The more acidic a lake becomes, the fewer species it can support. Plankton and invertebrates are among the first to die from acidification, and when the pH of a lake drops below 5, more than 75 per cent of its fish species disappear. This causes a ripple effect in the food chain, and has a significant impact on fish-eating birds, such as loons. Not all lakes exposed to acid rain become acidified. Bases found in certain types of rock and soil help to neutralize acidity.