Pollutants

Air pollutants are any particles or compounds that contaminate the air around us, at levels that are harmful to us or the environment.

Generally, they come from burning fossil fuels to provide energy for homes and industry, and to power planes, trains and automobiles.

The smog of the early industrial revolution is thankfully a thing of the past. Now most pollutants are much too small to see without a microscope. They are the invisible killers. And the nastiest of them are Nitrogen dioxide (NO2), Particulate Matter (PM) and Ozone (O3).