Odor - The Electronic Nose Artificial Olfaction Technology - page 96

Table 4.4 Methods used for elimination of Odor

1 Physical Aqueous cleaning

Air ventilation
Absorption to activated
charcoal

2 Chemical Combustion

Neutralization oxidation
Chemical absorption

3 Biological Microorganism

Antimicrobial agent

4 Sensory Masking with air freshener

Fig. 4.7 An odor classification system

economic front, loss of property value near odor causing operations/industries
and odorous environment is partly a consequence of offensive odor. Figure 4.6
shows the relationship between odor and human reactions related to well-being and
health. Table 4.4 list the methods used for eliminating unpleasant/hazardous
odor (Fig. 4.7 ).

4.7 Odor Objective and Classifications

The signals are obtained by measuring the change in the sensor's electrical
properties upon exposure to a gas. Next, the system converts these signals to
digital form, reduces data complexity in the preprocessing stage, and then employs
pattern recognition to classify the odor.
There are three basic ways to classify odors.

• By likes or dislikes
• By associations
• By chemical structures.

Likes and dislikes are specific because tastes differ. Association becomes
complicated because associations are different and odorant possesses different
qualities. Chemical classes or structures are very interesting ways of classifying
odors. They are grouped in families according to molecule structure.