Acid deposition is more than acid rain that includes both wet and dry forms of deposition capable of forming acid when mixed with water. The acid rain site at the US Environmental Protection Agency provides a hub from which much useful information is available. [local] Acid rain forms when atmospheric moisture reacts with emissions such as SO₂, SO₃, NO₂ and NO₃, generalized as SO_x and NO_x. Acid deposition has deleterious effects on surface water (streams and lakes). If the underlying bedrock has considerable lime deposits the effect of acid rain is lessened. In areas where hard water is common, acid rain will not change the pH of lakes and streams to the same degree as soft water lakes and streams. Not only aquatic ecosystems are affected. Acid rain reacts with soil minerals that are needed by trees and other plants. Acid rain is also harmful to people and buildings. The problem is extensive (see map) especially for areas downwind from the source of pollution emission. Using low-sulfur fuel, providing for SOx removal from emissions and using alternative energy sources are some of the solutions.