odores

Odors, or odores in some languages, refer to volatile chemical cues detected by the olfactory system. They arise from mixtures of volatile compounds that interact with receptors in the nasal epithelium, producing a percept of smell. Odors vary in intensity, quality, and hedonic value, and perceptions depend on concentration, chemical composition, context, and individual factors such as genetics and prior exposure. Prolonged exposure can lead to olfactory adaptation or fatigue, reducing sensitivity.

The study of odors falls under olfactometry and olfactory science. Quantifying odors often uses sensory methods such as detection thresholds and odor intensity scales. Units such as odor units (OU) per cubic meter standardize concentration relative to human detection thresholds, and GC-O combines gas chromatography with human panels to link odor notes to specific compounds. Odor activity values (OAVs) estimate each compound's contribution to an overall odor.

Common sources include natural processes (decay, fermentation, flowers) and human-made activities (industrial emissions, food processing, fragrances). Odors can signal safety hazards (gas leaks, spoiled food) or environmental concerns, and thus are subject to regulation and management in air quality and wastewater contexts.

In culture and industry, odors are studied for aroma profiling in foods and perfumes, as well as for consumer comfort and nuisance control in urban planning and facility management. The term odour is widely used in British English and many other languages, while odor is common in American English.