Ozone (O3) is a gas composed of three oxygen atoms. It is highly reactive colorless to bluish gas with a pungent odor.
For our healt is very dangerous so called ground level ozone.
Ground level ozone is formed by chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOC). This occurs when pollutants emitted by traffic, power plants, industrial plants, chemical plants, refineries and other sources, chemically react in the presence of sunlight.
Ozone acts like aggressive and powerful oxidizing agent and causes respiratory problems and inflammation of airway.