Acid rain can cause immediate damage to the cells of plants and animals as well as prolonged effects of residual damage in the future. Most directly, living cells require a balanced pH level in order to grow and divide properly. Acid rain can reduce the pH level of a cell, interrupting the typical functioning of mitosis.
Air pollution leads to an accumulation of carbon dioxide in the atmosphere that results in acid rain when the excess carbon dioxide combines with molecules of water vapor. The result is precipitation with a low pH level. Many plants and animals are sensitive to acidity and can experience damage if pH levels drop too far below neutral.
In particular, young plants are susceptible to damage from acid rain, as rootlets and leaf shoots are especially delicate structures. This can interrupt the plant's growth on an immediate basis, preventing the plant from dividing its cells and acquiring mass.
As a landscape experiences acid rain on a prolonged basis, these acidic chemicals can disrupt the flow of nutrients to plant life, destabilizing the local ecosystem. When local plants struggle to survive and grow, the animals that feed on them see their own sources of nutrients diminish. Areas where acid rain is common typically have soil conditions with low pH levels, and this often prohibits the growth and survival of some plants. As a result, local animals must either develop new dietary habits or flee to areas more suitable for their nutritional needs.