Fragrance is a mix of more than 3,500 chemicals that gives personal care, cleaning and other products their smell. Many of these are toxic, and exposure can cause a range of health harms. Fragrance ingredients are found in most products that we use, including perfumes and scented body lotions. Glance at the label of any such product, and you’ll find some ingredient that is listed simply as “fragrance.”
Unlike foods, which must meet rigorous government standards to ensure quality and safety, most fragranced products don’t need to be regulated before being sold to consumers. The exceptions are perfumes and scented body sprays that are applied directly to the skin. These are typically alcoholic solutions of 10-25 percent perfume concentrate, with an added amount of alcohol to provide a watery texture that holds the scent and allows it to be absorbed by the skin. A typical bottle of perfume may contain up to 100 different chemicals, although not all are needed for the fragrance effect. Several of these are used as fixatives, which help the other chemicals in the perfume last longer by binding with them.
The components of a perfume are usually classified according to one or more identifiable dominant odours, and the resulting groups are known as fragrance families. For example, floral perfumes include odours from flowers such as jasmine, rose and lily of the valley; citrusy blends include lemon and orange oils; spicy blends feature aromas such as cinnamon and clove; and woody fragrances are based on scents from trees like sandalwood and cedar. These classifications do not, however, capture all the subtlety of a perfume’s scent, and even perfumes that are designated as belonging to one family will often have undertones of other fragrance materials as well.
Perfumes are made from natural plant and animal oils, or synthetically manufactured. Those from plants are obtained through distillation or the maceration process in which the material is soaked in oils that serve as solvents, capturing heavier molecules. The enfleurage method, which involves placing petals or herbs in an open container of alcohol, is now rarely used. Synthetic aromatics can be produced through the chemical synthesis of raw materials such as phenol or acetone. Generally, they are less expensive than natural perfume ingredients.
The odours of the base notes are what give a perfume its depth and character. They appear a few minutes after the top and middle notes disappear, and are typically odours such as tobacco or musk. The base notes also act as a fixative, helping to hold the more volatile odours in the perfume for a longer period.