The diagram illustrates how pollutants produced by modern human activities lead to acid rain and subsequently contaminate ecosystems and the food chain.
Overall, emissions from several man-made sources rise into the atmosphere, where they are absorbed by clouds and transported over long distances. When these polluted clouds release precipitation, acid rain falls on land and water bodies, allowing toxic substances to enter living organisms through soil and waterways.
In the first stage, four major sources – housing, transport, factories and power stations – release a mixture of gases and particles. These include carbon dioxide, sulphur dioxide, nitrogen oxides and mercury, along with other compounds. As the emissions rise, they accumulate in clouds, which gradually absorb the pollutants and become increasingly contaminated.
Next, the polluted clouds move across countries and even continents before producing rainfall. This acid rain falls onto hills and fields, damaging trees and other plants, and it also reaches rivers and lakes via runoff. As pollutants are deposited into soil and water, they are taken up by vegetation or aquatic life and then passed on to animals and humans through the food chain.