Which statement best defines odor threshold?

• A. Concentration at which odor is detectable
• B. Concentration where odor fatigue occurs
• C. Concentration at which it ignites
• D. Concentration at which it changes color

Answer: (A)

Odor threshold is the lowest concentration of an odorant in air that a person can detect by smell. It reflects how sensitive our sense of smell is to that substance and can vary with individuals and conditions. This is different from odor fatigue (where continued exposure reduces detection), ignition (the point at which something catches fire), or a color change (a visual property). So the statement that best defines odor threshold is the concentration at which the odor is detectable.