Scent

Scent is the quality of a smell, usually produced by volatile chemical compounds that evoke a perceivable odor. In everyday language, scent often refers to pleasant smells, though in science an odor can be neutral, pleasant, or unpleasant.

The sense of smell, or olfaction, begins when odor molecules reach the nasal cavity and bind to specific olfactory receptor neurons. Signals are transmitted to the olfactory bulb and higher brain areas, where they are identified and associated with memories and emotions. Perception depends on concentration, temperature, prior exposure, and mixture interactions.

Scent sources are natural and synthetic. Natural scents derive from flowers, fruits, woods, and spices; synthetic fragrances are built from chemical classes such as esters, terpenes, musk compounds, and aldehydes. In perfumery, scents are structured in top, middle, and base notes to create a lasting composition.

Applications span the flavor and fragrance industry, consumer products, environmental monitoring, and pest management through semiochemicals. Scent can influence behavior and mood, and memories of scents are strongly tied to the limbic system, affecting preferences and recall.

Measurement of scent uses olfactometry and odor criteria (thresholds, intensity, hedonic tone) and analytical methods like GC-olfactometry to link chemical components with perceived odors.