1. Air pollution.

2.  Pollution of the atmosphere by toxic substances is called air pollution.  Air pollution has dramatically increased due to human activity. Burning of fossil fuels (oil,gas and coal)

3. Air pollution.  Examples include the boiler in your home, or cars and motorcycles in traffic. Industry and power plants also cause a lot of air pollution.

4. Air pollution.  Some gases react with water to form acids. If it rains, these acids fall down with the rain. This is called acid rain.  The acid damages the limestone in buildings. Many forests in Europe have been affected by acid rain.  Another form of air pollution is the increase in carbon dioxide.

6. Air pollution.  An important measure to reduce air pollution is the installation of filters on the chimney stacks of plants and factories.  Saving energy is an important issue.