the artificial removal or masking of unpleasant-smelling gaseous substances that are formed as a result of the putrefaction of organic substrates (human and animal wastes, foodstuffs, corpses). Deodorizing materials (deodorants) include substances that prevent decay and substances that destroy or mask the odor. The following are used as deodorants: ferrous sulfate, calcium hypochlorite, Formalin, potassium permanganate, zinc chloride, and coal and wood tars as well as various substances capable of adsorbing unpleasant-smelling gases, such as wood charcoal and peat. In many cases, ozone is added to the air (using forced ventilation) in order to remove undesirable odors. Deodorants (ozonizers) are charged with liquids containing pine and essential oils.