Fragrances in the Environment: Properties, Applications, and Emissions

Olfactory stimuli are processed in the human brain in a complex integrative system with other senses, and intimately wired to cortical areas related to the formation of memories, emotions, survival instincts, and language. These findings support the notion that the sense of smell imprints emotional value to objects and events, triggers memories and feelings which affect our moods and judgement, with repercussions on our behaviour and interpersonal relationships. This might explain our fascination with fragrances and pleasant scented materials, a trait that we seem to share with our ancestors and whose social and cultural significance changed over the centuries. Currently, it represents a multi-billion-dollar industry with application in numerous consumer products. With such production rates worldwide, fragrances naturally become a concern for their potential hazardous effects on humans and the environment. First only from natural origin and now predominantly synthetic materials, this wide array of chemicals has several uses according to their physicochemical properties but can impact all environmental compartments and life forms. This chapter gives a comprehensive overview about the types, classification, properties, production rates and main uses of fragrance compounds, as well as the main emission sources to the environment, potential toxicity, and regulatory actions currently in place to prevent hazardous incidences.