Ozone is a gas found in the air. It is a form of oxygen, made up of three atoms of oxygen. High up in the atmosphere, ozone helps shields us from the sun’s ultraviolet rays. At ground level, ozone is a harmful air pollutant and a main part of city smog.
Ozone forms when sunlight interacts with air pollutants. Being exposed to too much ozone can cause damage to the lungs. Breathing air polluted with ozone is very bad for people with lung diseases.