Read the text choosing the correct words.

Air pollution occurs when the concentrations of (harmful, painful, injurious)substances become high enough to cause the atmospheric environment to become toxic. Air pollutants can be gaseous, liquid or (dependable, stable, solid) in form, and can come from natural as well as human sources. Examples of natural sources of air pollution include forest fires, volcanic pollution and dust. Human sources of air pollutants include (injections, diffusions, emissions) from industry, agriculture, forestry, transportation, power generation, and space heating.

Air pollution can threaten the health of human beings, trees, lakes, crops, and animals. Abundant amount of air pollution changes natural atmospheric processes, causing acid rains, ozone holes, and enhancing greenhouse effect.

INDUSTRIAL SMOG is considered to be the most serious type of air pollution. Smoke and oxides of that are (revealed, released, let out) by burning coal and oil containing minor amounts of sulfur is the cause. Industrial smog has been known to cause air pollution disasters. One of the worst occurred in London in December of 1952. Five days of stagnant air brought about high-pressure systems caused between 3,500 and 4,000 deaths. Industrial smogs in London were called (bean soups, pea soupers, smog soupers).

ENERGY CRISIS

There has been an enormous increase in the global demand for energy in recent years as a result of the industrial development and population growth. Supply of energy is, therefore, far less than the actual demand.

Primary sources of energy today are fossil fuels which include coal, oil and gas. Fossil fuels are non-renewable resources, and their reserves are being depleted much faster than new ones are being made. Another problem is that burning fossil fuels produces a great amount of carbon dioxide and other greenhouse gases, thus contributing to the greenhouse effect and polluting the environment. On the other hand, fossil fuels have a number of advantages that have to be taken into consideration.

Among the main pros of fossil fuels we can enumerate the following:

1) Combustion of fossil fuels generates a large amount of usable energy and fossil fuels are considered as high-efficiency and stable fuels.

2) Fossil fuels are more easily available as compared to any other fuels – coal is cheap and is a highly reliable source of energy. It is easy to transport from one place to another, it is not necessary to build these power stations close to the location of the source of the fuel. Oil or natural gas can be carried from one place to another, very easily by the means of pipelines.
3) There is a benefit in the industry's ability to control pollution by using clean-burning coal technology.

The disadvantages of using fossils fuels lie in the direct impact to the environment:

1) Fossil fuels are non-renewable resources, they are constantly dwindling. As a result, there will be more demand and less supply of fossil fuels in the future. This is likely to increase the price of fossil fuels manifold (= many times).
2) The extraction of fossil fuels destroys natural habitats of plants and animals and leads to deforestation and causes irreparable harm to marine environment during drilling (this phenomenon is known as marine pollution).
3) Consumption generates greenhouse gases, causes acid rain and, in some cases, results in direct pollution through oil spills. On combustion of fossil fuels, a large amount of carbon dioxide is released into the atmosphere. In the atmosphere, it absorbs heat and contributes to the greenhouse effect. When the percentage of carbon in the atmosphere increases, it leads to elevation in the average temperature of the earth's surface and results in global warming.

A possible alternative to fossil fuels now is nuclear energy. Nuclear energy is a very important and productive energy source for today and it is considered to be a good alternative to fossil fuels as it does not produce greenhouse gases and does not contribute to the greenhouse effect and air pollution. We may look through the facts of its efficiency along with the destructive results that this energy may bring with incompetent using.

There are many pros, or advantages, of nuclear power plants:

1) Nuclear fuel is compact and the term of its use is fairly long. Nuclear power plants are consumer-oriented and become necessary in those places where there is acute shortage of fossil fuels and other sources of producing electricity. One more advantage is the small cost of this energy and relatively minor construction costs.

2) From an ecological point of view, such nuclear energy is the best way to diminish emissions in the atmosphere.

3) In recent years a substantial increase of oil prices has been taking place. This, in turn, causes an increase of prices for electricity generated by thermal power plants using fossil fuels. Nuclear electricity is much cheaper than electricity generated by oil, coal and gas due to the high cost for their production and transportation.

4) Another advantage of nuclear energy is that it does not produce emissions as fossil fuels and has low consumption of uranium for energy production, a large amount of energy is wrested from a small amount of fuel. It is highly efficient.

However, the use of nuclear energy has its downsides:

1) If an accident takes place in the storage, consequences could be terrible for humankind.

2) Also, people have not found ways to dispose of nuclear wastes safely. And this is a huge problem. Today, many countries argue about where to store the wastes: at the bottom of seas or in deserts? And who will do it on their territory?

3) Further, the accidents like the Fukushima nuclear reactor disaster and the Chernobyl nuclear power plant accident make many people reconsider the use of nuclear energy.

However, nuclear energy still remains the energy of the future. Its use promises many advantages if we can reduce the risk of nuclear accidents and can effectively eliminate wastes. If all of these problems are solved, nuclear energy can replace all other forms of energy.

Which of these conventional sources of energy seems more efficient to you? Why?

Due to the increasing global energy consumption and the probable depletion of the world’s non-renewable energy sources, ways of exploring and using alternative energy are being undertaken. Using alternative energy sources, such as solar energy, wind energy and etc., can be both beneficial and difficult. Let us explore the different pros and cons of the major alternative energy sources.
A major advantage of renewable energy is that it is renewable – therefore, it is sustainable and will never run out. More importantly, renewable energy produces little or no waste products that may pollute or have harmful effects on the environment.
The general disadvantage of using renewable energy is that it is difficult to generate large quantities of electricity similar to that of conventional fossil fuels. Another common problem among alternative energy sources is the reliability of the energy supply. Since it is naturally generated, renewable energy supply relies on the current weather conditions.
Another disadvantage of alternative energy source is that it is relatively more expensive to set up the equipment necessary for generating this source of energy.

Here are the advantages and disadvantages of alternative energy sources:
• Solar energy: the sun is a great source of energy since it is free and efficient. It is possible to maximize the energy given by the sun to replace the traditional electricity.

But there are limitations – areas at high latitude and places with frequent rains are places not capable of producing efficient solar energy.

• Wind energy is also an efficient electricity source. It is possible for wind energy to replace up to 20 percent of the total electric consumption in the future. It is also a very environmentally-friendly source of energy since there are no harmful gases produced in the process of converting the energy. Location is a very important factor in using wind energy, high latitudes and coast lines are good places to set up windmills.

A relatively big land area is also needed to put up a sufficient number of windmills.

• Hydroelectricandtidal energy come from water. Hydroelectric energy is mainly sourced from dams. Tidal energy, on the other hand, uses the natural tides of the ocean. The production of energy from water is another clean way of producing energy. However, there are several disadvantages. Putting up river dams as sources of hydroelectric energy is very expensive, while tidal energy source depends much on the ocean. There are only 9 places worldwide that are suitable for this kind of energy source. And tidal energy power plants are also said to provide negative effects on migratory birds and fish.

• Biomass consists of fermented animal waste, agricultural crops, grains and other natural products. It can be used to produce alcohol and also replace gasoline needs. It maximizes waste materials as an alternative energy source.

A drawback is that it still produces greenhouse gases.

Alternative energy sources, although they are renewable, also have some disadvantages. But their unfavourable effects are relatively smaller than the harmful effects of the conventional fossil fuels. The hunt for a cost-efficient and environmental friendly alternative energy source does not stop.

			1. Which alternative sources are illustrated in these photos? 2. Look at the picture below and comment upon it.

Date: 2016-04-22; view: 3378