Ozone is a colorless gas with a special fishy smell. Ozone decomposes slowly at room temperature. Ozone is one of the strongest chemical oxidants known and it plays an important role in air pollution. Under the action of ultraviolet rays, ozone reacts photochemically with hydrocarbons and nitrogen oxides to form photochemical smog with a strong stimulating effect.

【Health hazards of ozone pollution】

The lower troposphere of the atmosphere, ozone is also contained, but its concentration is much lower than that of the stratosphere. In unpolluted air, the concentration of ozone in the lower atmosphere is generally ( 0.005-0.05) × 10-6. At this concentration, ozone is harmless. Contrary to the beneficial ozone in the upper stratosphere, low-altitude ozone is a harmful gas with a pungent odor and a biocidal effect.