Acid Rain is caused by pollution containing sulfur dioxide, nitrogen oxide, and ozone ( SOý, NOx, and Oý ) is released into the air. These chemicals are absorbed into clouds and results in Acid Presipitation ( Acid Rain, Acid Snow, Acid Hail, Acid Sleet ). When the chemicals aren't absorbed into clouds, they can drift for miles and fall to the ground, resulting in Acid Deposition, or dry deposition. When Acid Rain falls into water it is mixed in with the normal water and causes the pH of the entire body to be raised. Measurments on the pH ( potential Hydrogen ) scale, rise exponentialy, thus, a lake with a pH of 4 is ten times as acidic as a lake with a pH of 5, and a lake with a pH of 3 is 100 times as acidic, After many rain falls of Acid rain, the pH of a normal lake ( 5.8 ) to 4. Acid Rain has been known to reach the acidicy of pH 2, ( battery acid has a pH if 1 ) this is a drastic change, as normal rain is average pH 5.2. Acid Rain can dissolve limestone and chalk, and corrodes outdoor structures. Statues and monuments that are left unprotected can fall victim to the unpredjudiced destruction of acid rain. Acid Rain reacts to different types of soil and rocks in two ways. 1) Acid rain will dissolve alkaline rocks and soil, or will neutralize the alkalinity. 2) Acid rain will increase the acidicy of already acidic rocks and soil, such as granite, or the soil which results from corroded granite. Acidic chemicals, and alkaline chemicals react to each other by reducing the alkalinity or acidicy of each other. Which ever has the strongest pH level, usually will neutralize or reduce the pH of the other, but after the reaction is complete, both substances have undoubtably changed, their pH moved closer to neutral ( pH 7 ). This knowledge led to the use of Salting. Salting ( dropping salt, chalk, or limestone into lakes and streams ) is a done to reduce the acidicy of the water, and neutralize the water, counteracting the effects of the acid rain. This involves literally tonnes of salt, and an Airplane with a bombay. This is only a temporary solution, as putting salt into the water will not stop the acid from coming, it just neutralizes what is already there.