It should be noted that the dilution of the actual odorous emissions is the physical process of the dilution of odorous emissions from a source that occurs in the ambient air or in a ventilated room. The “receptor” (citizen down wind or occupant in a room) sniffs the diluted odor. The dilution ratio is an estimate of the number of dilutions needed to make the actual odor emission “non-detectable” (detection threshold). If the receptor detects the odor, then the odor in the atmosphere is above the threshold level (supra threshold).