Another way is ultraviolet radiation. Ozone is a powerful oxidizer, which aggressively attacks organics. Our bodies are organic and ozone cannot differentiate good organics and bad organics. Although there are no documented deaths due to ozone, it should be dealt with caution and common sense. Chlorine and fire are also oxidizers, but we have learned to work safely and control them.
Ozone is no different.
Ultraviolet radiation from the sun creates ozone by splitting off oxygen atoms from the nitrogen oxides emitted by auto exhausts. This is the origin of smog encountered in urban areas. Trees emit hydrocarbons called terpenes. These byproducts of photosynthesis combined with sunlight can create enough ozone to produce a forest haze commonly familiar in forests or mountains. Because if ozone has attached and combined with an odor causing substance, it will revert back to ordinary oxygen.