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Unit 16 Air Pollution

1 Introduction

  1. Read the text title and hypothesize what the text is about. Write down your hypothesis.

1.2 What do you know concerning this issue? List your ideas in the table left column “I know”.

I know that...

I have learnt that...

1.3 If you biow answers to these questions write them down in the space given after each question.

1

What does the term “pollution” mean?

2

Which factors effect on ecosystems?

3

What natural building materials are destroyed by atmospheric acids?

4

Do you know the situation concerning forests in Europe?

5

What ancient monuments are suffering because of acidic fumes?

6

Do you know the first major source of air pollution?

7

What are the newest sources of air pollution?

    1. Circle in the list the words and expressions you know. Write down their translation in the table and calculate the percentage of your lexical competence.

1

pollution

9

chemical modification

2

toxic substance

10

barren landscape

3

to suffer from

11

to separate from

4

vegetation

12

limestone

5

to be responsible for

13

industrial area

6

metabolic regulator

14

to damage

7

to be destroyed by

15

corrosive gases

8

fume

16

widespread

How does the air taste, feel, smell, and look in your home or your neighborhood? It is possible that wherever you live, the air is contaminated to some degree. Smoke, haze, dust, odors, corrosive gases, noise, and toxic compounds are present nearly everywhere, even in the most remote, pristine wilderness. Air pollution is generally the most widespread and obvious kind of environmental damage. According to the Environmental Protection Agency (EPA), some 147 million metric tons of air pollution are released into the atmosphere each year in the United States by human activities. Total worldwide emissions of these pollutants are around 2 billion metric tons per year. The air in a typical industrial city can contain unhealthy concentrations of hundreds of different toxic substances; indoor air can be even worse.

Over the past twenty years, air quality has improved appreciably in most cities in Western Europe, North America, and Japan. At the same time, however, we have discovered dangers from air pollutants that did not exist or were not recognized in the past. Manufacturing, shipping, use, and disposal of thousands o f new super toxic chemicals have introduced a great variety of new hazardous materials into the air we breathe. We will examine the major types and sources of air pollution. Air pollution has existed as long as there has been an atmosphere. Perhaps the first major human source of air pollution was fire. Natural Sources of Air Pollution

It is difficult to give a simple, comprehensive definition of pollution. The word comes from the Latin pollutus, which means made foul, unclean, or dirty. Some authors limit the use of the term to damaging materials that are released into the environment by human activities. There are, however, many natural sources of air quality degradation. Volcanoes spew out ash, acid mists, hydrogen sulfide, and other toxic gases. Sea spray and decaying vegetation are major sources of reactive sulfur compounds in the air. Forest fires create clouds of smoke that blanket whole continents. Trees and bushes emit millions of tons of volatile organic compounds, creating, for example, the blue haze that gave the Blue Ridge Mountains their name. Pollen, spores, viruses, bacteria, and other small bits of organic material in the air cause widespread suffering from allergies and airborne infections. Storms in arid regions raise dust clouds that transport millions of tons soil. Bacterial metabolism of decaying vegetation in swamps and of cellulose in the guts of termites and ruminant animals is responsible for, as much as two-thirds of the methane

(natural gas) in the air.

Plant Pathology

In the early days of industrialization, fumes from furnaces, refineries, and chemical plants often destroyed vegetation and created desolate, barren landscapes around mining and manufacturing centers. The copper-nickel smelter is a spectacular and notorious example of air pollution effects on vegetation and ecosystems. There are two probable ways that air pollutants damage plants. They can be directly toxic, damaging sensitive cell membranes much as irritants do in human lungs. Within a few days of exposure to toxic levels of oxidants, discoloration occurs in leaves due to chlorosis (bleaching of chlorophyll), and then dead spots develop. If injury is severe, the whole plant may be killed. Sometimes these symptoms are so distinctive that positive identification of the source of damage is possible. Often, however, the symptoms are vague and difficult to separate from diseases or insect damage.

Another mechanism of action is exhibited by chemicals, such as ethylene, that act as metabolic regulators or plant hormones and

disrupt normal patterns of growth and development. Ethylene is a component of automobile exhaust and is released from petroleum refineries and chemical plants. The concentration of ethylene around highways and industrial areas is often high enough to cause injury to sensitive plants. Some scientists believe that the devastating forest destruction in Europe and North America may be partly due to volatile organic compounds.

Forest Damage

In the early 1980s, disturbing reports appeared of rapid forest declines in both Europe and North America. European forests are dying at an alarming rate. West German foresters estimated in 1982 only 8 percent of their forests showed air pollution damage. Similar damage is reported in Czechoslovakia, Poland, Austria, and Switzerland. Again, high elevation forests are most severely affected. This is a disaster for mountain villages in the Alps that depend on f orests to prevent avalanches in the winter. Sweden, Norway, the Netherlands, Romania, China, and also have evidence of growth reduction of seedling and premature tree death.

Buildings and Monuments

In cities throughout the world, some of the oldest and most glorious buildings and works of art are being destroyed by air pollution. Smoke and soot coat buildings, paintings and textiles. Limestone and marble arc destroyed by atmospheric acids at an alarming rate. The Parthenon in Athens, the Taj Mahal in Agra, frescoes and statues in Florence, medieval cathedrals in Europe, and the Lincoln Memorial and Washington Monument in Washington, D.C., are slowly dissolving because of acidic fumes in the air. Medieval stained glass windows in Cologne's gothic cathedral are so porous from etching by atmospheric acids that pigments disappear and the glass literally crumbles away. Restoration costs for this one building alone are estimated at three to four billion German marks ($1.5 to $2 billion).

Air pollution also damages ordinary buildings and structures. Corroding steel in reinforced concrete weakens buildings, roads, and bridges. Paint and rubber deteriorate due to oxidization. Limestone, marble, and some kinds of sandstone flake and crumble.

We have defined air pollution as chemical or physical changes brought about by either natural processes or human activities, resulting in air quality degradation. The major sources of air pollution are transportation, industrial processes, stationary fuel combustion, and solid waste disposal.

We also looked at some unconventional pollutants. Indoor air pollutants, including formaldehyde, asbestos, toxic organic chemicals, radon, and tobacco smoke may pose a greater hazard to human health than all of the conventional pollutants combined. Odors, visibility losses, and noise generally are not life threatening but serve as indicators of our treatment of the environment. Some atmospheric processes play a role in distribution, concentration, chemical modification, and elimination of polluta.

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