Fragrance is a class of chemicals that give personal care, cleaning and other products their distinctive smells. Glance at the label of any product and chances are it contains one or more fragrance ingredients. Fragrance can be made from natural or synthetic chemicals. Some fragrance compounds are toxic and may cause health problems. The International Fragrance Association (IFRA) develops standards that manufacturers use to ensure safe use of fragranced products.
Perfume, aroma and scent all refer to agreeable odors: the perfume of roses, the delicious aroma of fresh bread, the delicate fragrance of a flower. The word fragrance is closer to the odors of growing things, while the more formal perfume suggests a manufactured or concentrated odor.
The scent of a perfume usually has three structural parts: the top note, which is the refreshing, volatile odour perceived immediately; the middle notes, which are more floral or fruity and form the “heart” of the fragrance; and the base notes, which provide depth and solid character. The base note compounds are often rich and musky, with a deep smell that lasts longer than the top or middle notes.
Various families of fragrances exist, based on the dominant odour of the compounds used to make them. These include the citrus family, dominated by such odours as lemon, lime or grapefruit; the single floral family, including such odours as jasmine, rose, lily of the valley or gardenia; and the woody family, featuring odours like patchouli, sandalwood or cedarwood. The most opulent perfumes combine several of these odours, in a combination called a bouquet or accord.