Many buildings and monuments are made of stone, and many buildings use stone for decorative trim. The sculpture is located in Dresden, at the corner of Bautzner Straße and Eck Glacisstraße. This religious medieval sculpture, made of sandstone, has been degraded by the acidification of air and rains. Our concern is that air pollution, particularly in urban areas, may be accelerating the normal, natural rate of stone deterioration, so that we may prematurely lose buildings and sculptures of historic or cultural value.

This weathering process, over hundreds of millions of years, turned the Appalachian Mountains from towering peaks as high as the Rockies to the rounded knobs we see today. Stone weathers (deteriorates) as part of the normal geologic cycle through natural chemical, physical, and biological processes when it is exposed to the environment. In Europe, where buildings are much older and pollution levels have been ten times greater than in the United States, there is a growing awareness that pollution and acid rain are accelerating the deterioration of buildings and monuments. However, we are becoming aware of an additional concern: many of our historic buildings and monuments are located in the areas of highest acidity. When you hear or read in the media about the effects of acid rain, you are usually told about the lakes, fish, and trees in New England and Canada. In addition, the prevailing wind direction brings storms and pollution to the Northeast from the Midwest, and dust from the soil and rocks in the Northeastern United States is less likely to neutralize acidity in the rain. This pattern of high acidity is caused by the large number of cities, the dense population, and the concentration of power and industrial plants in the Northeast. The areas of greatest acidity (lowest pH values) are located in the Northeastern United States. To find the distribution of rain acidity, weather conditions are monitored and rain samples are collected at sites all over the country. Environmental Protection Agency Geographic distribution of acid rainĪcidity in rain is measured by collecting samples of rain and measuring its pH. Much of the Black Forest was indeed black because so much of the green pine needles had been destroyed, leaving only the black trunks and limbs! You also might notice how acid rain has eaten away the stone in some cities' buildings and stone artwork.Ĭredit: U.S. I've seen some of the acid-rain damage to the evergreen forests in the Black Forest of Germany. Many plants, such as evergreen trees, are damaged by acid rain and acid fog. Some fish and animals, such as frogs, have a hard time adapting to and reproducing in an acidic environment. But in areas, such as some of the Rocky Mountains and parts of the northwestern and southeastern United States, where limestone does not naturally occur in the soil, acid rain can harm the environment. Because bases counteract acids, these soils tend to balance out some of the acid rain's acidity. Often soil is slightly basic (due to naturally occurring limestone, which has a pH of greater than 7).

The environment can generally adapt to a certain amount of acid rain. That is why forests and lakes in the countryside can be harmed by acid rain that originates in cities. Although acid-rain gases may originate in urban areas, they are often carried for hundreds of miles in the atmosphere by winds into rural areas. From these gases, airborne sulfuric acid (H 2SO 4) and nitric acid (HNO 3) can be formed and be dissolved in the water vapor in the air. Exhausts from cars cause the formation of nitrogen oxides in the air. The burning of fossil fuels (coal and oil) by power-production companies and industries releases sulfur into the air that combines with oxygen to form sulfur dioxide (SO 2).

The precursors, or chemical forerunners, of acid rain formation result from both natural sources, such as volcanoes and decaying vegetation, and man-made sources, primarily emissions of sulfur dioxide (SO 2) and nitrogen oxides (NO x) resulting from fossil fuel combustion.

Acid rain also removes minerals and nutrients from the soil that trees need to grow.Īcidic precipitation can be caused by natural (volcanoes) and man-made activities, such as from cars and in the generation of electricity. That aluminum may be harmful to plants as well as animals. Acid rain leaches aluminum from the soil. Visit Media to see details.ĭead or dying trees are a common sight in areas effected by acid rain like these woods in the Jezera Mountains in the Czech Republic.

Acrid risk of rain 2