Odor Monitoring

The methods of odor monitoring are reviewed by Kinsman [975] and by Wetteman and Wilson [1838]. 

The concentration of odorants in gases can be measured by the absorbance in the ultraviolet region [1612,1616]. The absorbance of odorized gas is much higher than the absorbance of untreated gas. Gaschromatography with an electrochemical detector is also suitable [1822] for analysis of mercaptans. 

---

E. B. Klusmann. Odor monitoring at Southern California Gas Company. In Odorization, volume 3, pages 407-423. Institute of Gas Technology, Chicago, IL, Southern California Gas Co, 1993. 

Mitrovics, J. Ulmer, H. Weimar, U. Gopel, W., Modular sensor systems for gas sensing and odor monitoring The moses concept, Acc. Chem. Res. 1998, 31, 307-315. 

Detection. Many people can detect hydrogen cyanide by odor or taste sensation at the 1 ppm concentration in air, most at 5 ppm, but HCN does not have an offensive odor and a few people cannot smell it even at toxic levels. Anyone planning to work with hydrogen cyanide should be checked with a sniff test employing a known safe concentration. This test should be given periodically. Several chemical detection and warning methods can be employed. The most rehable are modem, electronic monitors based on electrolytes that react with hydrogen cyanide. 

None of the foregoing methods will tell the frequency or duration of exposure of any receptor to irritant or odorous gases when each such exposure may exceed the irritation or odor response threshold for only minutes or seconds. The only way that such an exposure can be measured instrumentally is by an essentially continuous monitoring instrument, the record from which will yield not only this kind of information but also all the information required to assess hourly, daUy, monthly, and annual phenomena. Continuous monitoring techniques may be used at a particular location or involve remote sensing techniques. 

The rate of the reaction is followed by monitoring file disappearance of file purple odor due to iodine. The following data are obtained at a certain temperature. 

Odorization is a primary concern for any gas transmission company [813,1379]. Accurate injection of the odorant, proper monitoring techniques, and complete record maintenance are important factors in developing and sustaining a successful odorization program. 

A review has been presented concerning the aspects of odorization. Important points to consider are which pipelines require odorization, the detectable limits of gas odor, odorants and odorizing considerations, and monitoring a pipeline system to ensure that the odorization program is meeting the regulatory requirements [574]. 

Chemical sensors are widely used to monitor hazardous and combustible gases [65]. Applications include safety control in industrial applications, surveillance of boilers and other devices which are operated with natural gas as well as more sophisticated areas like cooking control and odor determination [66]. 

A sensor array named the electronic nose is a rapid and relatively simple technique that can be used for monitoring wastewater odors (Stuetz et al., 2000). The electronic nose uses sensors of varying affinities to characterize an odor without reference to its chemical composition. 

Supplemental measures that may be considered are a fixed oxygen monitoring system, a low pressure storage bottle alarm(s) or odorization of the stored CO2 gas. 

Seventeen individual resident case histories were taken and symptoms reported over the past month ranged from mild (foul odors) to severely irritating of sinuses, eyes, headache, bleeding nose and peeling skin. Symptoms dining the time of the air quality monitoring done in this report ranged from no unusual odors (5 individuals) to noticeable odor with no symptoms (4), to it smelled horrible (2)... 

Fig. 21.10. Total ion (TIC) and selected ion monitoring (at m/z = 104) chromatograms of the headspace of the acceptable and unacceptable flavor samples. (Redrawn/redrawn from J. Chromatogr., 351, R.A. Sanders, and T.R. Morsch, Ion profiling approach to detailed mixture comparison. Application to a polypropylene off-odor problem, 525-531, Copyright (1986) with permission from Elsevier.)...

---