Biomedical Engineering Reference
In-Depth Information
Table 4.7 Categorization of odor evaluation methods from the viewpoint of indicator objectives
Objective of indicator
Higher accuracy
Lower accuracy
Concentration of Individual
constituent
Gas chromatography
Detection tube
Monitoring device for specified
constituents
Odor index, odor unit and odor
intensity
Triangular odor bag
method
Simplified olfactory methods
Odor sensor including electric nose
Sensory direct indication for odor
intensity
Odor quality including hedonic
tone
Sensory direct indication for odor
hedonic tone
Electric nose
Table 4.8
Categorization
of
odor
evaluation
methods
from
the
viewpoint
of
application
purposes
Category
Summarize method analysis
Examples of the evaluation
method
Evaluation for
compliance
Obligatory method based on the law.
Necessary to ensure sufficient
accuracy for judgment in legal
action. Generally expensive
method
Triangular odor bag method,
dynamic olfactometer, gas
chromatography, etc
Evaluation for
voluntary
management
Not obligatory. Use in voluntary
management. Easier and cheaper
methods are better. Highly
accurate methods are not always
necessary. Highly frequent
monitoring is possible
Detection tube, odor sensor,
subjectively direct rating for
intensity or hedonic tone, etc
Evaluation for
characterization of
odor emission
source
Characterization of time-dependent
change of odor emission from the
odor source, detailed composition
of odorous constituents and
contribution of constituents to
sensory magnitude of odor
Continuous monitoring using
odor sensor, GC
olfactometer, GC/MS,
electric nose
Mainly an odor emission consists of a complex mixture of various odorous
compounds. Individual chemical compounds analysis of odor using analytical
monitoring is not practical. Because of that, odor sensory methods are normally
used to measure such odor instead of instrumental methods. It is also required and
useful for monitoring odor from: source of odor emissions and in the ambient air.
These two different conditions required different approaches for measuring odor.
Also odor samples collection is easily available for a source emission than for an
odor in the ambient air. Note that due to atmospheric dilution, the odor in the
ambient air is typically much lower in intensity than it is at source. Thus the
sensitivity of the odor sensory method must be significantly greater for measuring
ambient odor than for source odor emissions.
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