Effects on Historical Monuments
By Chris Dinesen Rogers, eHow Contributor updated: April 22, 2010 Pollution 's Impact on Historical Monuments Significance Pollution negatively impacts historical monuments and buildings around the world, from the Acropolis in Greece to the America ' s own Lincoln Memorial. The threat is in the risk of losing these irreplaceable structures forever. Many of these monuments have cultural and aesthetic value that is beyond price. Acid Rain One of the more destructive forms of pollution is acid rain. Acid rain occurs when fossil fuel emissions containing sulfur dioxide combine with moisture in the air to form acidic precipitation. When acid rain falls on historical monuments of limestone or marble , a chemical reaction takes place which has a corrosive effect on these structures. The reaction dissolves the material, leading to permanent damage. Global Warming According to the National Climatic Data Center, global temperatures have risen during the past century at a rate of 0.11 degrees Fahrenheit per decade. The concern with historical monuments lies in the temperature impacts on the chemistry. Heat acts as a catalyst, speeding the rate of chemical reactions. The fate of historical monuments becomes more uncertain, and the urgency to take action increases. Global warming occurs when greenhouse gases such as carbon dioxide trap radiant heat at the earth 's surface, which causes temperatures to rise . Contributing Factors Other factors contribute to the rate of damage to historical monuments. An increase in humidity provides the necessary environment for corrosive chemical reactions in the absence of rain. Likewise, changes in sun radiation can temporarily raise temperatures on the surface of monuments, mimicking the effects of global warming on a specific site. Prevention/Solution Fortunately, the levels of atmospheric sulfur dioxide have declined in recent years, mitigating some effects of pollution on historical monuments. According to the U.S. Environment Protection
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