Unit used to measure scent emission of people and objects; one olf is defined as the scent emission of an "average person", a sitting adult that takes an average of 0.7 baths per day and whose skin has a total area of 1.8 m2; the scent emission of an object or person is measured by specially trained personnel comparing it to normed scents.

Note: The olf should not be confused with the of unit of scent immission (as opposed to emission), the decipol which also takes into account the ventilation system's air volume flow.