Ozone

Ozone, the triatomic form of oxygen (O3), is a gaseous atmosphericconstituent. In the troposphere, it is created both naturally and byphotochemical reactions involving gases resulting from human activities(smog). Tropospheric ozone acts as a greenhouse gas. In the stratosphere,it is created by the interaction between solar ultraviolet radiation andmolecular oxygen (O2). Stratospheric ozone plays a dominant role in thestratospheric radiative balance. Its concentration is highest in the ozonelayer.