Read the text and complete the sentences with the missing words. The first letter of the word is given
The word "smog" consists of words "smoke" and "fog". It describes a kind of air pollution caused by tiny particles in the air. The word was first mentioned at the beginning of the 20th century in London. At that time people used to burn large amounts of coal which caused a mixture of smoke and sulfur dioxide in the air. Today, we can notice a photochemical smog in many megacities. It is caused by the reaction of the chemicals in the air with the light. Smog comes from transport emissions, production areas and power stations. Smog makes the environment unattractive, reduces visibility and affects our health and well-being. It also makes breathing difficult, and it's extremely dangerous for people who suffer from asthma. It affects animals and plants in the area, too.

1. Smog =
   [ ] +
   [ ].
2. Smog is a kind of
   [ ].
3. Burning coal causes smoke and
   [ ] dioxide.
4. Transport burns fuel and exhausts
   [ ].
5. [ ] is a widely spread disease in the cities affected by smog.