Please understand the main function of this device is that the relative strength of a smell can be shown numerically. This device can also provide you “Odor Classification” as second function and reference for discrimination of a smell by using two gas sensors the principle is uses the output value from two gas sensors that have distinctive characteristics and provide different output values.
When outputs from Sensor A and Sensor B are applied to vertical and a horizontal axis, figure shows degree of the “angle” between the peak of each output and the starting point. When you measure a pure single substance with this device in a chamber and get reading for each substance, you can make your own table, which is correlation table of a substance name and the discrimination reference value.
In case of compound smell, you cannot use the above-mentioned correlation table, for example when you find similar reading of hydrogen sulfide, you cannot consider that it is compound smell and main component is hydrogen sulfide. You cannot disregard chemical reaction of combined components and cannot consider it is compound smell of hydrogen sulfide mainly.
When measuring the effect of deodorization, or judging when a certain smell is removed, the discrimination reference value can be observed before deodorization. You will find intensity has fallen after deodorization, but discrimination reference value would be the same. If you deodorize by the adsorbing methods such as activated carbon, you can explain that the strength level is reduced without an unpleasant smell ingredient’s adsorbing uniformly and composition hardly changing.
There is a technique of masking which deodorizes with alcohol or fragrance. In this case, the perceived smell level falls dramatically but this is just, as you know, masking over the smell. Since this device also reacts to alcohol and fragrance, the intensity of the reading is possibly increased.