Classification of Malodors


All odor molecules do not stimulate the sensory receptors in the nose. In general, only specific part of a molecule is able to stimulate the receptor in the nose and transmit a stimulus to brain. Malodors are classified into third parts according to their active stimulus content:

Fatty acids: They include sourish odors, sweat odors and odors arising out of oil olive processing plants. Such kind of odors commonly result from sweating or spoiling such as souring. The odors classified under this heading do not cause concern because they are less problematic and readily avoidable odors.

Suplhur Constituents: Such odors generally consist of organic sulphide and mercaptans. These constituents are spread from rotten materials, animals like skunk, anaerobic reactions in water treatment plants and decay of cucurbita or similar vegetables.

Nitrogen Constituents: The said odors is generally caused by amines and their sources are fish, decay of cadaver and droppings,etc. Some other nitrogen constituents also contribute to smoky odors.
In addition to above classification, reactive structure of some malodor molecules include phosphor, nitrogen and selenium sulphide on a very rare basis. In such cases, these emitted odors are highly strong and very offensive.

From the chemical aspect, it can be seen from the above table which chemical compounds cause the malodors that we perceive.

In practice, malodors are not comprised of a sole compound as specified above. Most of them contain sulfur and nitrogen as a result of collection of several reactive substances.