The olfactory bulb is located in the front section of the brain in many animals, but in humans it is located in the bottom portion. The cells within the nasal cavity detect odors in the form of chemical particulates within the air and send the received information to the olfactory bulb. The olfactory bulb is believed to tell odors apart, amplify sensitivity to odors, identify important odors and send the information to higher level areas of the brain for further information processing, according to Wikipedia. While, from its structure, it appears that the olfactory bulb could exclusively perform all of these tasks, scientists are unsure whether it is the sole structure within the brain that performs these functions.
The olfactory bulb is comprised of five layers: the granule cell layer, the internal plexiform layer, the mitral cell layer, the external plexiform layer and the glomerular layer. These layers are listed in order from internal to external, and each perform specific tasks related to the neural processing of odors, according to Wikipedia,