(=aroma threshold value, =OTV, =ATV)) is a measure of odor intensity of a substance. It is defined as a minimal concentration of that substance that can be detected by human nose. Some substances can be detected when their concentration is only few miligrams per 1000 tonnes which is less than a drop in olympic swimming pool. Odor threshold value can be expressed as a concentration in water or concentration in air.
Examples of some substances with strong odor.