What is Odor?
'''odor''' or '''odour''' is a volatilized [[chemical compound]], usually at a very low concentration, which humans and other animals perceive by the [[sense]] of [[olfaction]]. Odors are also called '''smells''', which can be used to describe both pleasant and unpleasant odors. The words '''fragrance''', '''scent''', or '''aroma''' are used mostly by the [[food]] and cosmetic industry to describe a pleasant odor, and is sometimes used to refer to [[perfume]]s. On the other hand, the words '''stench''', '''reek''', and '''stink''' are used specifically to describe unpleasant odors. == Basics == Odor is a [[sensation]] caused by [[molecule]]s dissolved in air. The widest range of odors are made up of [[organic compound]]s although some [[Inorganic compound|inorganic]] substances, such as [[hydrogen sulfide]] and [[ammonia]], are also odorants. The [[perception]] of an odor effect is a two step process. First, there is the physiological part; the sense of the [[stimulus]] by receptors in the nose. After that the psychological part follows. The stimuli are processed by the region of the human brain which is responsible for smelling. Because of this, an [[Objectivity (science)|objective]] and [[Analysis|analytical]] measure of odor is impossible. While odor feelings are very personal perceptions, individual reactions are related to [[gender]], [[Ageing|age]], state of health and private affectations. Common odors that people are used to, such as their own body odor, are less noticeable to individuals than external or uncommon odors. For most people, the process of smelling gives little information concerning the [[ingredients]] of a substance. It only offers information related to the emotional impact. However, experienced people, such as [[flavorist]]s and [[perfumer]]s can pick out individual chemicals in complex mixes through smell alone. == Odor analysis == The concentrations of odorant in [[Germany]] are defined by the “Olfaktometrie” since the 1870s. In this connection it's about the standard method to d