Fragrance is an odorant in the form of a mixture of aroma compounds. It may be derived from natural sources or synthetic and is added to a wide variety of personal care products and other manufactured goods to provide pleasant scents, enhance appearance and/or mask undesirable odors. Currently over 5000 different fragrance chemicals in countless combinations are used in cosmetics and other consumer goods. Some of these ingredients have been linked to a wide range of health problems including allergies, respiratory irritation, skin irritation and even cancer. Most of these chemicals are found in a growing number of household cleaning and laundry products such as aerosol sprays, shampoos, deodorants, body washes and dryer sheets.
Fragrances are composed of a combination of odorous chemicals skillfully assembled by perfumers. Until the nineteenth century, most perfumes were made from natural aromatic oils. Today most are formulated from synthetic ingredients. A fine perfume may contain more than 100 components. The components of a perfume are classified as top, middle and base notes and may be combined in several ways. The top note provides a fresh, volatile odor which evaporates quickly; the middle note, which is more mellow and rounded than the head, and lasts about 20-60 minutes; and the base note, which lingers for 2-4 hours.
The perfume industry uses a system of classification called the fragrance pyramid to distinguish the constituents of each fragrance. It is important to realize that the groupings do not reflect a completely objective or definitive character for any given fragrance; many perfumes, even those designated as belonging to a single family, possess aspects of several families. For example, a perfume categorized as being in the “single flower” family contains nuances of the other floral families, especially the rose, carnation and iris.
Besides the actual odorants, a perfume must also contain solvents to dilute and dissolve the fragrance compositions and to give it its characteristic body. The most commonly used solvent is alcohol, particularly ethanol. Perfume-oil dilutions are known as eau de toilette and eau de cologne; they contain lower concentrations of the perfume than those in “fine” perfumes.
Manufacturers use a variety of additives in addition to fragrance chemicals, such as preservatives and colorants to improve product shelf life, stabilize odors and impart a pleasing visual appearance. These are often hidden on ingredient lists under the generic term “fragrance,” because of the difficulty in defining their specific functions. Many of these ingredients are associated with adverse health and environmental effects, which can be avoided by using only purely organic, natural soaps, detergents, cleansers, moisturizers and other personal care products.