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Odor Threshold
The odor detection threshold is the lowest concentration of a certain odor compound that is perceivable by the human sense of smell. The threshold of a chemical compound is determined in part by its shape, polarity, partial charges, and molecular mass. The olfactory mechanisms responsible for a compound's different detection threshold is not well understood. As such, odor thresholds cannot be accurately predicted. Rather, they must be measured through extensive tests using human subjects in laboratory settings. Optical isomers can have different detection thresholds because their conformations may cause them to be less perceivable for the human nose. It is only in recent years that such compounds were separated on gas chromatographs. For raw water treatment and waste water management, the term commonly used is Threshold Odor Number (TON). For instance, the water to be supplied for domestic use in Illinois is 3 TON. Values * The threshold value is the concentration at which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Odor
An odor (American English) or odour (Commonwealth English; see spelling differences) is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive via their sense of smell. An odor is also called a "smell" or a "scent", which can refer to either a pleasant or an unpleasant odor. While "odor" and "smell" can refer to pleasant and unpleasant odors, the terms "scent", "aroma", and "fragrance" are usually reserved for pleasant-smelling odors and are frequently used in the food and cosmetic industry to describe floral scents or to refer to perfumes. Physiology of smell Sense of smell The perception of odors, or sense of smell, is mediated by the olfactory nerve. The olfactory receptor (OR) cells are neurons present in the olfactory epithelium, which is a small patch of tissue at the back of the nasal cavity. There are millions of olfactory receptor neurons that act as sensory signaling cells. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
