(Greek 'to smell') made of three atomic oxygen (O3) molecules, a gas that disrupts bacteria and colourants. Due to the occurrence of atomic oxygen, ozone is one of the strongest oxidising agents, and in higher concentrations is extremely toxic. Ozone is created by the effect of ultraviolet rays or electrical charges on oxygen. Very low concentrations of ozone are regarded as harmless, higher concentrations lead among other things to eye irritation and breathing difficulties among humans