ATMOSPHERIC POLLUTION

1.Pollution in cities.

All cities, especially the biggest ones, are a source of pollution for the atmosphere. Pollution come from cars, industries, power stations, central heating systems, etc. The result is that in the sky of a big city there is an accumulation of contaminating substances which can cause respiratory diseases and lack of visibility. This problem is called smog (smoke + fog = smog).

2. Global warming.

It has been discovered that, over the last one hundred years, the average temperature of the planet has risen from between 0.3 and 0.6 ºC. This phenomenon is known as global warming and it’s a result of the increase in the greenhouse effect.

Greenhouse effect is a natural phenomenon and it is essential for keeping the temperatures apt for living beings. However, certain polluting gases increase this effect and the temperatures increase too much. One of the main greenhouse gases is carbon dioxide (CO₂). This gas is released by the burning of coal,and oil as it happens in our cars and power stations. Furthermore, the deforestation also increase the CO₂ levels

Global warming has many harmful consequences: temperatures will rise, ice at the North and South Poles will melt, sea level will rise and many coastal cities will be flooded. We should save energy, stop using oil, gas and petrol and we should change to green energy (wind power, solar power, hydroelectricity...) and, of course, stop cutting down trees.

Some years ago it was discovered that there is an area where the ozone layer is getting thinner. This area is known the hole in the ozone layer. It was located over Antarctica but it is getting bigger and bigger; nowadays it affects South America and Australia, too. Harmful radiation affects our health causing skin diseases.

The disappearance of the ozone from the atmosphere is caused by contaminating substances called CFCs. These gases were used in refrigerators and aerosols but they have been substituted for other gases which do not pollute in an attempt to stop the deterioration of the ozone layer.