Carbon Monoxide

Carbon monoxide is a dangerous gas because it takes the place of oxygen in the blood and it does not leave the blood to go to the respiring cells. To make matters worse, it does not allow oxygen to take its place. Carbon monoxide is formed when fuels, such as oil or wood, are burnt in a limited supply of oxygen gas. If there is a fire in a mine, a lot of carbon monoxide is produced. This is very dangerous for miners because carbon monoxide is odourless and colourless, and the miners breathe it into their lungs without knowing it. Car exhaust fumes and cigarettes also produce carbon monoxide.

A person who has breathed in a lot of carbon monoxide cannot be revived by giving him oxygen gas. A blood transfusion would be needed urgently.

The Dangers of Smoking

Cigarettes are made from dried tobacco leaves. These leaves contain complicated carbon compounds which are taken into the lungs when the smoker inhales from the cigarette. When some of these complex carbon compounds are burnt they produce a thick, brown liquid called tar. This tar finds its way into the lungs where it can damage and block many of the microscopic alveoli. This prevents enough oxygen getting into the blood and a smoker may find it difficult to breathe, especially after exercise.

Some of the complex carbon compounds are extremely dangerous because they may cause cancer. When these compounds accumulate in the lungs they may cause a tumour to develop.

A burning cigarette also produces carbon monoxide which prevents enough oxygen reaching the tissues of the body. Smoking kills the cilia on the walls of the trachea. This means that dust particles, which are normally filtered out of the inspired air by the cilia, find their way into the lungs.

Industrial Pollution

In industrialized countries, particularly in the cities, the air is polluted with harmful substances. Dangerous gases are released into the atmosphere by factories and traffic. The main polluting gases are carbon monoxide and sulphur dioxide. Car exhaust fumes in Paris alone release over 6000 tonnes of carbon monoxide into the atmosphere in one year.

Sulphur dioxide dissolves in water to form sulphuric acid. This acid can damage the lungs if it is breathed in.

Sometimes an awful accident occurs when a dangerous gas leaks into the atmosphere from a factory. This happened in India in 1986. Thousands of people died or were seriously affected because of a gas leak from a chemical factory.

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