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Reading Selection, Lesson 12

Dissolving History

Dateline: January 1998, Athens, Greece

The Parthenon

The Parthenon stands with other ancient buildings on the Acropolis, which overlooks the city of Athens. These buildings have survived for thousands of years. However, air pollution, caused mainly by motor vehicle exhaust, has greatly damaged them.

Damage to a frieze on the Parthenon

Much of the damage caused to the Parthenon is the result of the action of acid rain dissolving the marble from which it was built.

A team of archaeologists, architects, ironworkers, and marble cutters has just started a new project. Its goal? To restore the Temple of Athena, a masterpiece of Greek architecture that was built in the fifth century b.c. The surface of the historic monument has been deteriorating for decades. It’s time for temple-saving action.

The workers know that they have a hard job ahead. Work on another famous Greek temple, the Parthenon, has been going on for nearly 60 years, and it's not done yet.

These buildings, like many monuments, are built of marble—one of the hardest stones. Why are they in need of restoration?

Wind and rain have always had an effect on buildings, but the main cause of deterioration is pollution. The problem is not just in Athens. In cities around the world, historic buildings are literally being dissolved away.

polluting factory

This steelworks is belching out smoke and gases, including those that cause acid rain. Pollution as bad as this is no longer allowed in the United States, but it is still common in some other countries of the world.

The major culprits are acid rain and smog (visible as a reddish brown haze), which is a problem in most of the world’s large cities. Both originate with the burning of fossil fuels, such as coal and petroleum. As these fuels burn, they give off gases, which include the pollutants sulfur dioxide and nitrogen oxides. One major source of nitrogen oxides is auto exhaust fumes. Sulfur dioxide is produced in particularly large quantities by coal-burning power plants and other industrial operations.

These gases rise into the atmosphere, where they combine with oxygen and water vapor. The sulfur dioxide becomes sulfuric acid, and the nitric oxides become nitric acid. Together, they form an acid solution that falls to earth as acid rain (or acid sleet or snow).All rain is slightly acidic, but acid rain does much more damage to buildings. It is especially harmful to buildings made from rocks that contain calcium carbonate or magnesium carbonate. Marble, used in many Athenian buildings, and the softer, even more vulnerable, limestone both contain carbonates. As years pass, the acid solution reacts with the surfaces of monuments and buildings and turns them into soluble substances. Acid rain can also attack paint and metals, and it forms a crust on the surface of glass.
Damage caused by acid rain

Acid rain has dissolved part of this artwork.

Not only does acid rain harm buildings, it damages trees and kills aquatic life and other organisms. To fight these effects, people around the world are applying a great deal of ingenuity to solve the problem of acid rain. In many countries, fossil-fuel-burning power plants and other industrial plants now remove some acidic gases from the waste products that would otherwise be dispersed through smokestacks. Also, special devices are being fitted to car tailpipes to remove some of these gases from exhaust fumes.

Until the source of the pollution is completely removed, any efforts to restore ancient buildings will be only stopgap measures. The team of workers on the Acropolis in Athens, in other words, is dealing with the symptoms, but not the cure.

What Can You Do About Acid Rain?

  • Use the car less. Carpool, use public transportation, ride a bike, or walk.

  • Conserve electricity. Most electricity is produced by coal-burning power plants, and coal emits a high amount of sulfur when it burns.

  • Study historical sites, buildings, or cemetery headstones in your area. Try to find out how they have been affected by acid rain.

  • Contact a local environmental group to see whether it has taken action about acid rain.


Questions

1. How is acid rain formed? Write a short paragraph describing this process.

2. Do an Internet search to find additional information on acid rain and its effects.

 

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