Answer:
1. Pollution is the introduction of harmful materials into the environment. These harmful materials are called pollutants. Pollutants can be natural, such as volcanic ash. They can also be created by human activity, such as trash or runoff produced by factories. Pollutants damage the quality of air, water, and land.
2. The majority of air pollution is the result of human activities. For example, increased fossil fuel combustion from motor vehicles, industrial factories and power plants all pump large quantities of air pollutants, such as carbon monoxide, ozone and nitrous oxides, into the atmosphere.
3. Air pollution is harmful to human health and also can harm pets and wildlife. Air pollution causes the formation of acid rain, which raises pH (a measure of acidity) in rivers and streams and destroys plants and trees.
