Question

What is smog and how is it caused?

Answer 1

Smog which occurs mainly because of air pollution, can also be defined as a mixture of various gases with dust and water vapor. Smog also refers to hazy air that makes breathing difficult.
it's causes are

Smog is often caused by heavy traffic, high temperatures, sunshine and calm winds. These are few of the factors behind increasing level of air pollutionin atmosphere. During the winter months when the wind speeds are low, it helps the smoke and fog to become stagnate at a place forming smog and increasing pollution levels near the ground closer to where people are respiring. 

Answer 2

Air pollution in large industrial cities (or urban regions) is called smog. . Smog can damage vegetation and decrease the productivity of some crops, injure flowers and shrubs and contribute to forest decline in some parts of Canada.

Smog affects everyone’s health. Some people are more vulnerable to the effects of air pollution than others. Those most sensitive to smog include:

• Young children
• Pregnant women
• The elderly
• Asthmatics
• People with heart problems
• Smokers
• People who work or exercise outdoors

 Warning signs that smog may be affecting your health:

• Mild breathing difficulties 
• Headache
• Eye, nose and throat irritation