It is a pale blue, highly poisonous gas with a strong odor.
Liquid ozone is a deep blue, strongly magnetic liquid.
Ozone is formed when an electric spark is passed through oxygen, and causes a detectable odor near electrical machinery. The commercial method of preparation consists of passing cold, dry oxygen through a silent electrical discharge. Ozone is much more active chemically than ordinary oxygen and is a better oxidizing agent . It is used in purifying water , sterilizing air, and bleaching certain foods. Ozone formed in the atmosphere from nitrogen oxides and organic gases emitted by automobiles and industrial sources, however, is a health hazard, and it may cause serious crop damage in some areas.