Reading 4: Acid Rain

READING 4

You should spend about 20 minutes on Questions 17 – 31 which are based on Reading 4.

Acid Rain

A

Acid rain is a broad term used to describe several ways that acids fall out of the atmosphere. A more precise term is acid deposition, which has two parts: wet and dry.

B

Wet deposition refers to acidic rain, fog, and snow. As this acidic water flows over and through the ground, it affects a variety of plants and animals. The strength of the effects depend on many factors, including how acidic the water is, the chemistry and buffering capacity of the soils involved, and the types of fish, trees, and other living things that rely on the water.

C

Dry deposition refers to acidic gases and particles. About half of the acidity in the atmosphere falls back to earth through dry deposition. The wind blows these acidic particles and gases onto buildings, cars, homes, and trees. Dry deposited gases and particles can also be washed from trees and other surfaces by rainstorms. When that happens, the runoff water adds those acids to the acid rain, making the combination more acidic than the falling rain alone.

D

Prevailing winds blow the compounds that cause both wet and dry acid deposition across state and national borders, and sometimes over hundreds of miles.

E 

Scientists discovered, and have confirmed, that sulfur dioxide (SO2) and nitrogen oxides (NOx) are the primary causes of acid rain. In the US, About two-thirds of all SO2 and one-fourth of all NOx comes from electric power generation that relies on burning fossil fuels like coal.

F

Acid rain occurs when these gases react in the atmosphere with water, oxygen,

and other chemicals to form various acidic compounds. Sunlight increases the rate of

most of these reactions. The result is a mild solution of sulfuric acid and nitric acid.

G

Over the past two decades, there have been numerous reports of damage to automotive paints and other coatings. The reported damage typically occurs on horizontal surfaces and appears as irregularly shaped, permanently etched areas. The damage can best be detected under fluorescent lamps, can be most easily observed on dark colored vehicles, and appears to occur after evaporation of a moisture droplet. In addition, some evidence suggests damage occurs most frequently on freshly painted vehicles. Usually the damage is permanent; once it has occurred, the only solution is to repaint.

H

The general consensus within the auto industry is that the damage is caused by some form of environmental fallout. "Environmental fallout," a term widely used in the auto and coatings industries, refers to damage caused by air pollution (e.g., acid rain), decaying insects, bird droppings, pollen, and tree sap. The results of laboratory experiments and at least one field study have demonstrated that acid rain can scar automotive coatings. Furthermore, chemical analyses of the damaged areas of some exposed test panels showed elevated levels of sulfate, implicating acid rain.

I

The popular term "acid rain" refers to both wet and dry deposition of acidic pollutants that may damage material surfaces, including auto finishes. These pollutants, which are released when coal and other fossil fuels are burned, react with water vapor and oxidants in the atmosphere and are chemically transformed into sulfuric and nitric acids. The acidic compounds then may fall to earth as rain, snow, fog, or may join dry particles and fall as dry deposition.

J

 Automotive coatings may be damaged by all forms of acid rain, including dry deposition, especially when dry acidic deposition is mixed with dew or rain. However, it has been difficult to quantify the specific contribution of acid rain to paint finish damage relative to damage caused by other forms of environmental fallout, by the improper application of paint or by deficient paint formulations. According to coating experts, trained specialists can differentiate between the various forms of damage, but the best way of determining the cause of chemically induced damage is to conduct a detailed, chemical analysis of the damaged area.

K

 Because evaporation of acidic moisture appears to be a key element in the damage, any steps taken to eliminate its occurrence on freshly painted vehicles may alleviate the problem. The steps include frequent washing followed by hand drying, covering the vehicle during precipitation events, and use of one of the protective coatings currently on the market that claim to protect the original finish. (However, data on the performance of these coatings are not yet sufficient.)

L

The auto and coatings industries are fully aware of the potential damage and are actively pursuing the development of coatings that are more resistant to environmental fallout, including acid rain. The problem is not a universal one -- it does not affect all coatings or all vehicles even in geographic areas known to be subject to acid rain -- which suggests that technology exists to protect against this damage. Until that technology is implemented to protect all vehicles or until acid deposition is adequately reduced, frequent washing and drying and covering the vehicle appear to be the best methods for consumers who wish to minimize acid rain damage.

Questions 1 – 4

Complete the summary of arguments below. Choose NO MORE THAN THREE WORDS from the passage for each answer. Write your answers in boxes 1 – 4 on your answer sheet.

Acid rain is a broad term used to describe the ways that acids fall. More precisely, it should be called … 1 … . The primary causes of acid rain are … 2 … and nitrogen oxides (NOX). …3 … occurs when these gases react in the atmosphere with chemicals. Acid rain may … 4 … material surfaces.

Questions 5 – 8

Answer questions 5 – 8 using NO MORE THAN FOUR WORDS from the passage. Write your answers in boxes 5 – 8 on your answer sheet.

5. How many parts does acid deposition have?

6. What does acidic water affect when it flows over and through the ground?

7. What does dry deposition refer to?

8. What makes dry deposition travel long distances?

Questions 9 – 12

Complete the table below. Use NO MORE THAN THREE WORDS from the passage. Write your answers in boxes 9 – 12 on your answer sheet.   

In the US … 9 … of all SO2	come from electric power generation
One-fourth of … 10 …
Sunlight increases	… 11 …
The damage to automotive paints                       typically occurs	… 12 …

Questions 13 – 15

Do the following statements agree with the views of the writer in Reading 4?

In boxes 13 – 15 on your answer sheet write

          YES                    if the statement agrees with the writer

          NO                      if the statement does not agree with the writer.

          NOT GIVEN      if there is no information about this in the passage

13. ‗Environmental fallout‘ refers to damage specifically caused by air pollution.

14. It is still not clear exactly how much damage acid rain does, and how much other forms of environmental fallout cause?

15. Frequent washing and drying and covering the vehicle will remain the best methods to minimise acid rain damage at least for a period of ten years in the future.