Applications of Machine Olfaction - The Electronic Nose Artificial Olfaction Technology - page 214

Table 8.4 Offensive agricultural by-products (threshold level for human detection and

recognition) [ 30 ]
Chemical odorant Formula Characteristic odor Detection Recognition

1.6 9 10 -2 2.1 9 10 -1 Acetaldehyde CH 3 CHO Pungent, fruity

Allyl mercaptan CH 2 CHCH 2 SH Strong garlic, coffee

Ammonia NH 3 Sharp, pungent

Amyl mercaptan CH 3 (CH 2 )4SH Putrid

Benzyl mercaptan C 6 H 5 CH 2 SH Strong

2.4 9 10 -1

Butylamine C 2 H 5 (CH 2 )2 NH 2 Ammonia-like, sour

Cadaverine H 2 N(CH 2 )5 NH 2 Putrid, decaying flesh

Chlorophenol ClC 6 H 5 O Phenolic, medical

7.7 9 10 -3 Crotyl mercaptan CH 3 CH = CHCH 2 SH Skunk-like

Dibutylamine (C 4 H 9 ) 2 NH Fishy

8.5 9 10 -2

Disopropylamine (C 3 H 7 ) 2 NH Fishy

4.7 9 10 -2 Dimethyamine (CH 3 ) 2 NH Putrid, fishy

1.0 9 10 -3

Dimethylsulfide (CH 3 ) 2 S Decayed vegetables

2.1 9 10 -3 Diphenylsulfide (C 6 H 5 ) 2 S Unpleasant

8.3 9 10 -1 Ethylamine C 2 H 5 NH 2 Ammonia-like

2.6 9 10 -3 1.0 9 10 -3

Ethyl mercaptan C 2 H 5 SH Decayed cabbage

4.7 9 10 -3 Hydrogen sulfide H 2 S Rotten eggs

Indole C 2 H 6 NH Nauseating, fecal

2.1 9 10 -2 Methylamine CH 3 NH 2 Putrid, fishy

2.1 9 10 -3 Methyl mercaptan CH 3 SH Decayed cabbage

2.4 9 10 -2

Propyl mercaptan CH 3 (CH 2 ) 2 SH Unpleasant

Putrescine NH 2 (CH 2 ) 4 NH 2 Putrid, nauseating

Pyridine C 6 H 5 N Disagreeable, irritating

2.2 9 10 -1 4.7 9 10 -1 Skatole C 9 H 9 N Nauseating, fecal

Sulfur dioxide SO 2 Pungent, irritating

Tert-butyl mercaptan (CH 3 ) 3 CSH Unpleasant, skunk

1.4 9 10 -2 Thiocresol CH 3 C 6 H 4 SH Rancid, skunk

1.4 9 10 -2 2.8 9 10 -1 Thiophenol C 6 H 5 SH Putrid, garlic-like

Triethylamine C 2 H 5 OH Ammonia-like, fishy

The odorous element of the atmospheric emissions is not, in most cases, a threat
to public health, since it is due to substances whose concentration level is far
below the threshold limit value set by health authorities. An E-nose intended for
evaluation of odor annoyance associated with atmospheric emissions was pre-
sented by Fabio et al. The E-nose included an array of conducting polymer sensors
for odor detection, and a fuzzy algorithm for data analysis [ 34 ].
The E-nose measurement system was designed based on an array of metal oxide
sensors used to classify three applications which include monitoring of wastewater
volatiles, detection of dry rot infections in buildings, and smart fire detection
systems [ 35 ]. Quality control of environmental measurement can be achieved with
speed, precision, and accuracy. E-nose developed with the use of SAW sensor
analyze vapor in air, water, and solid [ 36 ].