Fragrance is a mixture of chemicals that give perfumes and colognes their distinctive scent. It can be natural or synthetic, and it is added to a wide range of personal care products and cleaning supplies. Some fragrance chemicals are linked to a number of health problems, including dermatitis and allergic reactions. Many manufacturers don’t disclose the ingredients of their fragrances, which can contain more than 3,500 chemicals.
Perfumes are composed of three structural parts — head, heart, and base notes — that provide the initial impression, body, and lasting impression after application of a perfume. Head or top notes consist of light molecules that evaporate quickly, usually 5-30 minutes after application. They are made up of a mix of citrus, fruity, and herbal scents. Examples include 4711, Guerlain Eau de Cologne Imperiale, and Penhaligon’s Quercus.
Middle notes, also called heart notes, appear just prior to the disappearance of the top note compounds. Middle notes comprise a mix of a variety of floral scents, such as rose, jasmine, and lily of the valley. Modern perfumes may also contain synthetic floral odorants such as hedione, which imparts the fresh ozonous metallic marine scent associated with tropical ocean breezes.
Base notes, the last to appear before a perfume completely fades, add depth and solidity to a perfume. They are a blend of the middle notes and some other scents, such as tobacco and amber. The scents in perfumes may be natural or synthetic, and they may be combined with other additives such as preservatives, stabilizers, and dyes. Fragrance chemicals are often derived from petroleum, and companies that make perfumes or colognes buy fragrance mixtures from fragrance houses to develop their own proprietary blends.