Depending on its buffering capacity, soil may be affected by acid rain by having its pH level increased. The result of a high pH soil is the exhaustion of nutrients and minerals in the soil, including the release of harmful substances such as aluminium and other ecological concerns. Soil with an already high pH level is especially affected by acid rain.
Acid rain doesn't immediately destroy ecosystems, but the stunted growth resulting from acid-rain soil degradation becomes more serious over time. Among the nutrients and minerals dissolved by acid rain are magnesium, potassium and calcium. Plants must absorb these substances to grow. Nutrient deprivation and toxic exposure leaves plants susceptible to the elements, such as rainstorms and cold weather.
Acid rain may take the form of mist, snow or a dry dust. The corrosive effect of acid rain on soil is seen famously on the bald peaks of the Appalachian Mountains. The soil of these peaks is soaked from acidic fog, as are many high-elevation forests. While rain is always somewhat acidic due to oxidation, air polluted with nitrogen oxides and sulphur dioxide increase the pH of the rain to a harmful level. Rain with a pH between 2 and 4 is considered harmful.