The concept of acid rain is often misunderstood by the vast majority of the world, however, most realize that it is a problem. The burning of fossil fuels has released pollutants into our earth's atmosphere. Once airborne, the pollutants form acidic compounds by combining with water in the atmosphere, hence the name "acid rain". The precipitation then reaches the earth's surface by means of fog, mist, rain or snow, as well as in dry form. While the substances that produce acid rain also occur naturally, it is the man-made contributions that have transformed acid rain into an environmental problem. Acid rain causes the acidification of streams and lakes, contributes to damage of highly elevated trees, and also contributes to the cause of lung cancer and other major health problems to humans. Another concern about acid rain that has not been previously mentioned is the accelerating decay of building materials and paints, which includes many irreplaceable buildings, statues, sculptures, and monuments that are a part of our nation's cultural heritage. If these monuments are destroyed, they can never be replaced, which will be the focus of this report.
             Before speaking of the direct effects of acid rain on materials, the process of the formation of acid rain must be understood. We now know that the primary causes of acid rain are emissions of sulfur dioxide (SO ) and nitrogen oxides (NO ). When Sulfur is emitted into the air, it is in the form of the SO gas. Naturally, there is not a significant amount of SO gas in the air, so the gas transfers through a series of oxidation reactions, resulting in the formation of H SO , or sulfuric acid. This acid can then dissolve in rainwater and lower the pH of precipitation dramatically. On the other hand, NO gases are formed through a completely different process. Naturally, the atmosphere contains a large percentage of N gas. High temperatures associated with the burn...