Air Pollution

Air pollution refers to harmful materials in the air that have a negative effect on the environment and living things. These materials come in many forms, ranging from gases to fine liquids and even tiny particles of solids. Air pollution has been a major part of human society for hundreds of years, but humans have only come to understand its damaging effects in recent decades. Pollution has contributed to changes in Earth’s atmosphere that allow excessive heat and gases to harm the planet and its life. Air pollution may also carry poisonous materials that cause direct harm to living things.

Some kinds of pollutants, or harmful materials, affect the land and water. Other pollutants harm the air. These pollutants may...