Odor - Types

Types

Some odors such as perfumes and flowers are sought after, with elite varieties commanding high prices. Whole industries have developed around products to remove unpleasant odors (see deodorant). The perception of odors is also very much dependent upon circumstance and culture. The odor of cooking processes may be pleasurable while one is cooking, but not necessarily after the meal.

The odor molecules transmit messages to the limbic system, the area of the brain that governs emotional responses. Some believe that these messages have the power to alter moods, evoke distant memories, raise their spirits, and boost self-confidence. This belief has led to the concept of "aromatherapy" wherein fragrances are claimed to cure a wide range of psychological and physical problems. Aromatherapy claims that fragrances can positively affect sleep, stress, alertness, social interaction, and general feelings of well-being. However, the evidence for the effectiveness of aromatherapy consists mostly of anecdotes and lacks controlled scientific studies to back up its claims.

With some fragrances, such as those found in perfume, scented shampoo, scented deodorant, or similar products, people can be allergic to the ingredients. The reaction, as with other chemical allergies, can be anywhere from a slight headache to anaphylactic shock, which can result in death.

Unpleasant odors play various roles in nature, often to warn of danger, though this may not be known to the subject who smells it. An odor that is viewed as unpleasant by some people or cultures can be viewed as attractive by others where there is more familiarity or a better reputation.

It is commonly viewed that those holding an unpleasant body odor will be unattractive to others. But studies have shown that a person who is exposed to a particular unpleasant odor can be attracted to others who have been exposed to the same unpleasant odor. This includes smells associated with pollution.

What actually causes a substance to smell unpleasant may be different from what one perceives. For example, perspiration is often viewed as having an unpleasant odor, but it is actually odorless. It is the bacteria in the perspiration that cause the odor.

Unpleasant odors can arise from specific industrial processes, adversely affecting workers and even residents downwind of the industry. The most common sources of industrial odor arise from sewage treatment plants, refineries, animal rendering factories, and industries processing chemicals (such as sulfur) which have odorous characteristics. Sometimes industrial odor sources are the subject of community controversy and scientific analysis.

Body odor is present both in animals and humans and its intensity can be influenced by many factors (behavioral patterns, survival strategies). Body odor has a strong genetic basis both in animals and humans, but it can be also strongly influenced by various diseases and psychological conditions.