Sensing of Scent, Fragrance, Smell, and Odor Emissions from Biota Sources

People encounter enormous numbers of chemicals present in the outdoor atmosphere and/or in the various facilities they use daily. Despite such diversity, not many of them have necessarily the potential to draw human’s nasal attraction if their perception thresholds are in general not sufficiently low enough, regardless of abundance. In this sense, many types of scents, musks, fragrances, smells, odors, and pheromones are unique enough to draw a great deal of attention mainly by their presence at or near threshold levels which are far lower than those of common chemicals with poor odorant characteristics. It is known that most of the diverse characters of odor-related ingredients or expressions are commonly produced from various biota sources present in the biosphere, e.g., fauna, flora, bacteria, fruits, flowers, trees, meats, fresh/decaying foods, etc. In light of the environmental significance of the various odor types characterizing certain odorous events, it is crucially important to be able to describe, both qualitatively and quantitatively, the concentration levels and/or relative composition of both major and minor components giving rise to such odorous conditions. Despite many advances achieved over the past decades in the sensing and instrumental techniques for odor quantitation, it still remains of utmost importance to expand our knowledge on the exact nature of various odor types and improve our odor detection abilities.