title: [Classification of harmful gases].
abstract: The classification of harmful gases may be envisaged in various ways according to the criteria considered. The two aspects adopted here concern chemical and toxicological classifications. Chemical classification is in general based upon the nature of the elements constituting the gases, e.g. carbon, nitrogen, sulphur, phosphorus, halogen compounds and halogenated compounds, etc. Toxicological classification is envisaged on the basis of the concepts of toxicity itself. It may then be used to establish the scale of its degree based upon two principal factors: concentration and duration of exposure. However, certain observations suggest complex intoxication phenomena related to an overall number of factors which are generally considered in isolation.
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D005739:Gas Poisoning / Q000209:etiology; D005740:Gases / Q000145:classification* / Q000633:toxicity; D006801:Humans
chemical_list: D005740:Gases
vernacular_title: Classification des gaz délétères.