Which would be classified as a pollutant?

A pollutant is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource.

Any material that is capable of causing the degradation of an environment would be classified as a pollutant.

Explanation:

Pollutant is a substance that degrades and / or pollutes something, especially water or the atmosphere. It can enter the environment naturally, such as volcanic eruptions or human activities, such as burning coal and gasoline. As pollutants, we can mention: carbon monoxide, sulfur, suspended particles, lead, nitrogen oxide, ethylene, propane, butane, carbon dioxide, among others.

Pollutants can be in the form of gas, liquid, solid or energy.