4>EPA
c./
United States
Environmental Protection
Agency
Office of Research and
Development
Washington, DC 20460
EPA/600/R-92/047
March 1992
Reference Guide to
Odor Thresholds for
Hazardous Air Pollutants
Listed in the Clean Air Act
Amendments of 1990
AIR RISK INFORMATION SUPPORT CENTER
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EPA600/R-92/047
March 1992
REFERENCE GUIDE TO ODOR THRESHOLDS
FOR HAZARDOUS AIR POLLUTANTS LISTED IN THE
CLEAN AIR ACT AMENDMENTS OF 1990
Prepared for
Air Risk Information Support Center (Air RISC)
U.S. Environmental Protection Agency
Sponsored by:
Environmental Criteria and Assessment Office
Office of Health and Environmental Assessment
Office of Research and Development _ rnv:rrnment?! protection Agency
Research Triangle Park, NC 27711 P^ fU ibrsrv "/F"
~-'r^/; -.<; .'hc!.o:.'< r • :Hh Floor
Office of Air Quality Planning and Standards ;-, »'., -,
Office of Air and Radiation
Research Triangle Park, NC 27712
$Z) Printed on Recycled Paper
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DISCLAIMER
This document has been reviewed in accordance with U.S. Environmental Protection
Agency policy and approved for publication. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
11
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CONTENTS
Page
LIST OF TABLES v
LIST OF FIGURES vi
AUTHORS, CONTRIBUTORS, AND REVIEWERS vii
PREFACE ix
1. INTRODUCTION 1-1
1.1 THE CONCEPT OF ODOR THRESHOLD 1-2
1.1.1 Dimensions of Odor 1-2
1.1.2 Introduction to Olfactory Function 1-6
1.2 EVALUATION OF ODOR THRESHOLD INFORMATION ... 1-9
1.2.1 Criteria Used To Evaluate Odor Threshold
Information 1-9
1.2.1.1 Panel Size of at Least Six
per Group 1-10
1.2.1.2 Panelist Selection Based on
Odor Sensitivity 1-10
1.2.1.3 Panel Calibrations 1-11
1.2.1.4 Consideration of Vapor Modality
(Air or Water) 1-11
1.2.1.5 Diluent in Accord with Compound 1-12
1.2.1.6 Presentation Mode That Minimizes
Additional Dilution (Ambient)
Air Intake 1-12
1.2.1.7 Analytic Measurement of Odorant
Concentration 1-12
1.2.1.8 Calibration of Flow Rate and Face
Velocity (for Olfactometers) 1-13
1.2.1.9 Consideration of Threshold Type
(Detection or Recognition) 1-13
1.2.1.10 Presentation Series That Reduces
Olfactory Fatigue 1-13
1.2.1.11 Repeated Trials 1-14
1.2.1.12 Forced-Choice Procedure 1-14
1.2.1.13 Concentration Step Increasing by
a Factor of Two or Three 1-14
1.2.2 Critique of Odor Threshold Measurement
Techniques 1-14
in
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CONTENTS (cont'd)
1.3 ODOR THRESHOLDS IN RELATION TO RISK ASSESSMENT 1-16
1.3.1 Relationship Between Odor Threshold Values
and Health-Based Ambient Criteria 1-16
1.3.1.1 Background Exposure 1-18
1.3.1.2 Variability in the Odor Threshold
Data 1-18
1.3.1.3 Choice of Health-Based Ambient
Criteria 1-19
1.3.2 Theoretical Considerations: Is There a Link
Between Odor and Toxicity? 1-21
1.3.3 Conclusions 1-22
1.4 LITERATURE SEARCH AND REVIEW 1-23
1.4.1 Critiqued Odor Threshold Values 1-23
2. ODOR THRESHOLD DATA FOR INDIVIDUAL CHEMICALS AND
CHEMICAL CATEGORIES 2-1
3. REFERENCES 3-1
IV
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LIST OF TABLES
Number Page
1-1 Relationship Between Odor Threshold Values and Ambient
Criteria 1-22
2-1 Reported Odor Thresholds from All Sources 2-3
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LIST OF FIGURES
Number Page
1-1 An intensity function for 1-butanol 1-4
1-2 Relative slopes of psychophysical functions for ammonia and
hydrogen sulfide 1-5
1-3 Illustration of the normal range concept showing a potential
population distribution of olfactory sensitivities to
odorants 1-7
VI
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AUTHORS, CONTRIBUTORS, AND REVIEWERS
This document was prepared by TRC Environmental Consultants, Inc., under Contract
No. 68D90173 with the Environmental Protection Agency, Research Trianlge Park, NC,
Daniel J. Guth, Ph.D., Technical Monitor.
The following TRC Envionmental Consultants, Inc., personnel were involved in the
preparation of this document: Samuel S. Cha (Project Manager), Jocelyn R. Mellberg,
Gary L. Ginsberg, Ph.D., Karen E. Brown, Kara Raabe, and Joseph C. Coco.
The following scientists reviewed an earlier draft of this document and submitted
comments:
William S. Cain, M.D.
John B. Pierce Laboratory
Yale University
New Haven, CT
Dennis Demchak
Connecticut Bureau of Air Management
Hartford, CT
Carol A. Dupraz
Consultant
White Plains, NY
Sherry Selevan, Ph.D.
U.S. Environmental Protection Agency
Human Health Assessment Group
Washington, DC
Chon R. Shoaf, Ph.D.
U.S. Environmental Protection Agency
Environmental Criteria and Assessment
Office
Research Triangle Park, NC
Amos Turk, Ph.D.
Consulting Chemist
Danbury, CT
Susan F. Velasquez
U.S. Environmental Protection Agency
Environmental Criteria and Assessment
Office
Cincinnati, OH
Winona Victery, Ph.D.
U.S. Environmental Protection Agency
Region 9
San Francisco, CA
vn
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PREFACE
Many State and local agencies are developing or implementing programs to control
emissions of toxic air pollutants. To successfully carry out these programs, in many cases,
agency personnel must be familiar with a wide range of issues related to health, exposure,
and risk assessment for toxic air pollutants. However, locating appropriate sources of
information on these topics is not always an easy task. This reference guide to odor
thresholds has been prepared by the U.S. Environmental Protection Agency's (EPA's) Air
Risk Information Support Center (Air RISC) as a resource tool for State and local air
pollution control agencies and EPA Regional Offices to identify information regarding odor
thresholds for hazardous air pollutants.
Air RISC is operated by EPA's Office of Air Quality Planning and Standards (OAQPS)
and Office of Health and Environmental Assessment (OHEA). The key goal of Air RISC is
to provide technical assistance to State and local air pollution control agencies and EPA
Regional Offices, in obtaining, reviewing, and interpreting health, exposure, and risk
assessment information for air pollutants. Through Air RISC, State, local, and EPA
Regional Office personnel can request expert guidance and information on health, exposure,
and risk assessment issues and methodologies related to air pollutants.
In response to a large number of requests concerning the identification and interpretation
of odor thresholds for a variety of chemicals, Air RISC initiated the project that resulted in
this document. This document consists of three sections. Section 1 is an introductory
discussion of basic concepts related to olfactory function and the measurement of odor
thresholds. Section 1 also describes the criteria that are used to evaluate and determine the
acceptability of published odor threshold values. Section 2 contains the tabulated results of a
literature search and critical review of published odor threshold values for the chemicals listed
as hazardous air pollutants in the Clean Air Act Amendments of 1990 at the time of passage.
Each odor threshold value is evaluated according to the criteria discussed in Section 1 and a
geometric mean of the acceptable values is provided as the best estimate of the odor
threshold. Section 3 lists the references used in preparation of this report.
IX
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1. INTRODUCTION
The growing public concern about chemicals in the environment has resulted in
legislation such as the 1986 Superfund Amendments and Reauthorization Act, Title III, and
1990 Clean Air Act Amendment, Title III, air toxic provisions. Historically, local
environmental protection agencies report that odor complaints make up a large number of the
citizen complaints received. In general, the public does not understand the relationship
between odor and risk and believes "If it smells, it must be bad." Local agency staff
answering these complaints sometimes have to assess the potential health risk from exposure
to chemicals by relying on odor threshold values reported in the literature; unfortunately,
these reported odor threshold values vary considerably from one literature source to another.
It is not uncommon for reported odor threshold values of some chemical compounds to range
over three or four orders of magnitude. Major sources of variability include the type of data
source; differences in experimental methodology; and the characteristics of human olfactory
response, which demonstrate a great deal of interindividual variability.
A recent report from the American Industrial Hygiene Association reviewed and
critiqued odor threshold data ("Odor Thresholds for Chemicals with Established Occupational
Health Standards", American Industrial Hygiene Association, 1989). The project identified
and compiled experimental odor threshold references in the literature, and evaluated
methodologies used in published reports against a set of objective criteria. Using these
methods to eliminate questionable data, an attempt was made to estimate a better odor
threshold value for certain compounds if the information was available. The geometric mean
of the acceptable data was taken and is considered to be a reasonable estimate of the actual
odor threshold (American Industrial Hygiene Association, 1989).
This approach is now being used to focus upon the hazardous air pollutants listed in the
1990 Clean Air Act Amendment for EPA's Air Risk Information Support Center. One of the
major goals is to provide state and local agencies with data tables and an explanatory
narrative so that community odor perception can be properly evaluated and interpreted in
terms of chemical exposure and risk.
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A related issue is how to assess health risks when odors are detected. This could be
done by systematically comparing odor thresholds to guidelines or standards for ambient or
occupational exposure depending upon the population of concern. The purpose would be to
determine whether, or in which cases, the detection of odor is a suitable indicator of health
risk. Factors that affect this analysis are variability in the odor threshold data and in the
human olfaction mechanism and the choice of health-based ambient criteria and background
information pertinent to the particular case in which odors are detected.
This document contains a general background discussion of odor threshold
measurement, interpretation and use in risk assessment. Section 1.1 presents background
material on odor perception and odor properties. In Section 1.2, a brief review of odor
threshold methodology is given. Section 1.2 also describes the criteria used to evaluate the
odor threshold sources. Section 1.3 will discuss the use of odor thresholds as a tool in
assessing risk. Section 1.4 describes the literature search and review procedure. Summaries
of available odor threshold data are presented in tabular form in Section 2. Section 3
contains the references cited in the summaries and sources used during the research for this
report.
1.1 THE CONCEPT OF ODOR THRESHOLD
A brief review of the sensory properties of odor and some of the attributes of human
olfactory response is presented to facilitate understanding of odor threshold values.
1.1.1 Dimensions of Odor
The sensory perception of odorants has four major dimensions: detectability, intensity,
character, and hedonic tone. Odorant detectability (or threshold) refers to the theoretical
minimum concentration of odorant stimulus necessary for detection in some specified
percentage of the population. This is usually defined as the mean, 50% of the population;
however, it is sometimes defined as 100% (including the most insensitive) or 10% (the most
sensitive). Threshold values are not fixed physiological facts or physical constants but are a
statistical point representing the best estimate value from a group of individual responses. As
such, it may be an interpolated concentration value and not necessarily one that was actually
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presented. Two types of thresholds are evaluated: the detection threshold and the
recognition threshold. The detection threshold is the lowest concentration of odorant that will
elicit an olfactory response without reference to odor quality in a specified percentage of a
given population. In test procedures it is the minimum concentration of stimulus detected by
a specific percentage of the panel members. Additionally, Russian literature defines detection
thresholds as absolute thresholds (i.e., the lowest concentration that will produce any
measurable physiological change [e.g., as an electroencephalogram response] in the most
sensitive human subject).
The detection threshold is identified by an awareness of the presence of an added
substance. The recognition threshold is defined as the minimum concentration that is
recognized as having a characteristic odor quality by a specific percentage (usually 50%) of
the population.
Odor intensity refers to the perceived strength of the odor sensation. Intensity increases
as a function of concentration. The relationship between perceived strength (intensity) and
concentration can often be expressed as a power function, as follows (Stevens' Law):
S = kln
where 5 = perceived intensity of sensation, k = y-intercept, / = physical intensity of
stimulus (odorant concentration), and n = exponent of psychophysical function, typically less
than 1.0.
In logarithmic coordinates, Stevens' Law becomes log 5 = n log 7 + log K, which is a
linear function with slope equal to n. An intensity function for a standard odorant, 1-butanol,
is shown in logarithmic coordinates in Figure 1-1. The slope of the function varies with type
of odorant typically over a range from about 0.2 to 0.7. The slope of the function for
butanol shown in Figure 1-1 equals 0.66. This is an important consideration in the control of
odors. A discussion of odor intensity and how such curves are derived can be found in
Dravnieks (1972).
In air pollution control, we are often concerned with the "dose-response" or
psychophysical function, which is reflected by the slope. The slope also describes the degree
of dilution necessary to decrease the intensity. A low slope value would indicate an odor
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100
10
S.
I I I 1 I I I I
i i i T 11 i r
Neutral
Threshold
I I I I I I L-
I I I I I I I I
I I I I I I I I
10
100 1000
PPM Butanol (By Volume)
Figure 1-1. An intensity function for 1-butanol.
that requires greater relative dilution for the odor to dissipate; a high slope value indicates an
odor that can more quickly be reduced by dilution. Examples of compounds with low slope
values include hydrogen sulfide, butyl acetate, and the amines; those with high slope values
are ammonia and the aldehydes. In general, substances with low thresholds yield low slopes
and those with high thresholds show high slopes. The relative slopes of hydrogen sulfide and
ammonia are depicted schematically in Figure 1-2. Similar curves for other compounds can
be found in Dravnieks (1972). The difference in the degree to which these two chemicals
affect the olfactory system is apparent from this illustration. For a 1:1 mixture of ammonia
and hydrogen sulfide, ammonia is often perceived as the odor character of the mixture at
higher concentration levels. However, when diluted, or if the observer walks away from the
source, the hydrogen sulfide odor becomes the dominating odor character. This phenomenon
is commonly encountered at wastewater treatment plants.
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(0
I
Hydrogen Sulfide
Increasing Concentration of Odorant
Figure 1-2. Relative slopes of psychophysical functions for ammonia and hydrogen
sulfide. The schematic diagram depicts the steep odor
intensity/concentration slope for ammonia as compared to the shallow slope
for hydrogen sulfide. The difference in slopes means that at high
concentrations of both odorants, the predominant odor will be that of
ammonia, while at lower concentrations hydrogen sulfide will be detected.
The third dimension of odor is the character, in other words, what the substance smells
like. An American Society for Testing and Materials (ASTM) publication (Dravnieks, 1985)
presents character profiles for 180 chemicals using 146 descriptors, rated on a scale of 0 to 5.
The descriptors include such terms as fishy, hay, nutty, creosote, turpentine, rancid, sewer,
and ammonia.
The fourth dimension of odor is hedonic tone. Hedonic tone represents a judgment of
the relative pleasantness or unpleasantness of the odor. Perception of hedonic tone outside
the laboratory is influenced by such factors as subjective experience, frequency of occurrence,
odor character, odor intensity, and duration.
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1.1.2 Introduction to Olfactory Function
Human odor perception has a few functional aspects of particular relevance: sensitivity,
specificity, and somewhat independent processing of olfactory input by the cortex and more
primitive brain structures. The close coupling of molecular odorant recognition events to
neural signaling enables the nose to detect a few parts per trillion of some odorants (Reed,
1990). The molecular nature of recognition permits the nose to distinguish between very
similar molecules.
The initial events of odor recognition occur in a mucous layer covering the olfactory
neuroepithelium, which overlays the convoluted cartilage in the back of the nasal cavity.
Each of the millions of olfactory neurons in the middle layer of this epithelium extends a
small ciliated dendritic knob to the surface epithelial layer and into the overlaying mucus. As
in the immune system, receptors on different cells have different specificities. The binding of
a single odorant molecule to a receptor on this dendritic tip may be adequate to trigger a
neural signal to the brain. On each tip dozens of cilia increase the surface area available for
recognition events and may stir the local mucus, aiding in the rapid detection of small
concentrations of odorants. Individual receptors desensitize with use, temporarily losing their
ability to transduce signals.
The peripheral olfactory neurons project to the olfactory bulb from which signals are
relayed to the olfactory cortex and more primitive brain structures such as the hippocampus
and amygdala. This last structure affects whole brain-body emotive states. For further
information on the olfactory system physiology, see Dodd and Castellucci (1991).
Human response to odorant perception follows certain characteristic patterns common
among sensory systems. For example, olfactory acuity in the population conforms to a
normal distribution. Most people, assumed to be about 96% of the population, have a
"normal" sense of smell as depicted in Figure 1-3. Two percent of the population are
predictably hypersensitive and two percent insensitive. The insensitive range includes people
who are anosmic (unable to smell) and hyposmic (partial smell loss). The sensitive range
includes people who are hyperosmic (very sensitive) and people who are sensitized to a
particular odor through repeated exposure. Individual threshold concentrations may be
normally distributed around the mean value (e.g., Figure 1-3) or log-normally distributed. In
some instances, the threshold distribution is bimodel, with a small antinode that represents
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'Normal" Sense of Smell
AN
N
-Olfactory Sensitivity to Odorants
Figure 1-3. Illustration of the normal range concept showing a potential population
distribution of olfactory sensitivities to odorants.
people with a specific insensitivity, commonly called specific anosmia. For example, the
odor threshold for hydrogen cyanide is bimodally distributed since there are at least two
distinct groupings with markedly different abilities to detect hydrogen cyanide (Agency for
Toxic Substances and Disease Registry, 1988).
Another property of olfactory functioning includes adaptation to an odor, also known as
olfactory fatigue. These terms describe a temporary desensitization after smelling an odor.
After smelling a strong odor, a weaker near-threshold odor may not be detectable. For this
reason, odor threshold measurement studies must be carefully designed.
As mentioned in the previous section, mixtures of compounds such as ammonia and
hydrogen sulfide may have varying odor character depending on their relative concentrations.
All odorants have the ability to mask the odor of other compounds, in mixtures of appropriate
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proportions. Some mixtures of odorants may be perceived as qualitatively different from the
individual components (Foster, 1963; Mitchell and McBride, 1971). The perceived intensity
of a mixture, of two odors can be represented using a vector model. Two odors can be
thought of as the vectors A and B. The length of the vectors can represent the relative
intensities of the odors. The angle between the two vectors typically has a value of about
110 degrees. The vector model illustrates the nature of mixtures of odors. The intensities
are not simply additive. Two odors in concentrations that give similar intensities, when
added together can result in an odor with intensity that is approximately the same, but with a
slightly different character or quality than the two odors as perceived individually (Berglund,
1974).
A sensory property of odor that can cause confusion in organoleptic (i.e., sensory as
opposed to analytical) odor identification is that odor character may change with
concentration. For example, butyl acetate has a sweet odor at low concentrations, but takes
on its characteristic banana oil odor at higher intensities. Carbonyl sulfide has a "fireworks"
or "burnt" character at concentrations below 1 part per million (ppm) and "rotten egg"
character at higher levels. This, along with individual variability, accounts for discrepancies
in odor character reports. The odor character descriptors in this paper are based on a
combination of reports in the literature and experience in odor investigation.
The ability to discriminate between different odor intensities is very sensitive. It has
generally been found that concentrations higher or lower by 25 to 33 % are perceived as
different. In a carefully controlled study by Cain (1977), the average perceptible difference
between concentrations was 11%, ranging from 5 to 16% for different compounds.
As noted above, there are two basic types of odor thresholds: the detection threshold
and the recognition threshold. Detection is defined as the concentration at which the average
panel member notices an odor, but cannot necessarily identify it. The recognition threshold
is the lowest concentration at which the average panelist can identify a definite character of
the odor. The difference in concentration between detection and recognition thresholds can
vary from approximately twofold to tenfold. For example, Hellman and Small (1974) found
the detection and recognition thresholds of acetophenone to be 0.3 ppm and 0.6 ppm, which
is a twofold concentration difference. While for acrylic acid, the thresholds were found to be
0.092 ppm and 1 ppm, an 11-fold concentration difference.
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The order of presentation of odorants in experimental determination of odor threshold is
very important so as not to induce olfactory fatigue. The olfactometer commonly used in
recent odor threshold experiments is a device that dilutes samples of odorant with odor-free
air and presents the diluted samples to panelists in ascending order of concentration in two- or
threefold concentration steps. Panelists choose which of the three nozzles in a cup differs
from the other two. In this forced-choice procedure, panelists must pick a port whether they
detect a difference or not (i.e., panelists are asked to guess even if they discern no
difference). Odorous exhaust air from the olfactometer is removed through an exhaust line
outside the building to avoid odor build-up within the room. A thorough discussion of
olfactometers and odor threshold measurement is given in Dravnieks (1980).
1.2 EVALUATION OF ODOR THRESHOLD INFORMATION
Odor threshold determination has interested researchers for a century. Over this period,
hundreds of threshold measurements along with nearly as many measurement techniques have
been reported in the literature. Odor thresholds are often determined in a laboratory setting
using various methods to dilute odorants that are presented to a panel of subjects. In order to
consistently evaluate experiments of odor thresholds, which vary widely in design and
reporting detail, a set of standard criteria was established.
1.2.1 Criteria Used To Evaluate Odor Threshold Information
The method of presentation of the odorant is dependent upon what chemical odor
threshold is to be measured. In this report, only gas-air mixtures have been considered.
A delivery system that reduces the intake of unmeasured ambient air is most desirable.
A known concentration of odorant is delivered to the panel and responses are measured.
Usually a verbal response is taken by a monitor. Responses can include whether or not an
odor is detected, the strength of the odor, and odor quality (e.g., pleasant vs. unpleasant,
fishy, aromatic, etc.).
Once the responses of the panel are recorded, statistical methods can be used to
determine the odor threshold for either detection or recognition. Some of the important
variables of odor threshold measurement are discussed below.
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A set of criteria considered essential to any modern threshold determination procedure
was developed (see below). The sources with published odor thresholds (listed in Section 2)
were evaluated in terms of their conformity to these criteria. The criteria are summarized
below.
Sources that did not account for these criteria in their experimental design were not
accepted. For example, a random presentation series was accepted when concentration levels
were evaluated by different subjects (Gundlach and Kenway, 1939) but not when presented to
the same subjects. An exception would be when a random presentation to the same subjects
was used, but the interval between trials was long enough to permit reversal of olfactory
adaptation.
1.2.1.1 Panel Size of at Least Six per Group
In order to approximate the distribution of olfactory sensitivity in the population, it is
preferable to use a large number of subjects or, since this is often impossible, a smaller group
selected to represent the general population. Accordingly, to replicate the distribution curve
shown in Figure 1-3, it is preferable to use a larger panel with fewer trials rather than a small
panel (e.g., 2 or 4 subjects) with many trials. Additionally, panels of fewer than six subjects
reduce precision for a reliable mean value. Repeatability for individuals' threshold results are
poor (+18%); therefore, results should not be based on the repeated observations of less than
six panelists. However, there is a point beyond which more panelists become superfluous.
One study found that a pooled group of ten with one trial produced the same thresholds as a
group of thirty-six with five trial presentations (Punter, 1983). Odor threshold determinations
using fewer than six panelists or with the number of panelists not reported were not accepted.
1.2.1.2 Panelist Selection Based on Odor Sensitivity
Prospective panelists should be evaluated for olfactory sensitivity to the chemical
compounds in question. This will insure that the panel will not include judges with general
or specific anosmia. An early version of an ASTM threshold procedure (ASTM 1391-57
Syringe Dilution Method) recommended testing with only two all-purpose odorants, vanillin
and methyl salicylate. Subsequent studies showed that these compounds did not rate panelists
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properly. Panelists should be evaluated with a compound selected to represent the particular
chemicals under investigation, rather than with two standard compounds.
Physiological and personal factors to be considered when selecting a panel include
smoking, drug dependency, pregnancy, sex, and age. Smokers should be excluded from the
panel even though the effect of smoking on olfactory acuity is unclear. Studies have reported
results ranging from definite to no effect from smoking (see Cometto-Muniz and Cain, 1982,
for discussion).
Drug dependency and pregnancy are known to reduce and elevate odor perception,
respectively (Amerine et al., 1965). Anosmia due to drug dependency would be discovered
during screening. Similarly, prospective panelists being treated with high levels of
medication would be screened and omitted from the panel. Pregnant women should be
excluded as a precautionary measure.
As with smoking, results of investigations of changes in olfactory acuity due to age and
sex are in disagreement. The common conception has been that women are more sensitive
than men and that sensory acuity decreases with age. However, this may be too simplistic an
explanation. Recently, the approach has been to separate odor sensitivity from odor
identification ability (e.g., see Doty et al., 1984, for changes with age; Cain, 1982, for
differences between sexes).
Odor threshold determinations were not accepted if there was no screening of panelists
reported.
1.2.1.3 Panel Calibration
Panel odor sensitivity should be measured over time to monitor gross individual
discrepancies and maintain panel consistency. Individual variability is ±18% while
person-to-person variability can differ by four orders of magnitude. A daily rating of an
n-butanol wheel olfactometer would provide a quick and accurate measure of individual and
group variability.
1.2.1.4 Consideration of Vapor Modality (Air or Water)
Vapor modality (i.e., whether the odor measured is in the form of a gas-air mixture or
vapor over an aqueous or other solution) is determined by the test purpose and in turn
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determines the presentation method. The majority of reported thresholds are gas-air
measurements. Therefore, some criteria for the apparatus will pertain directly to gas-air
instead of vapor over an aqueous solution. Only gas-air mixtures were accepted in this
report.
1.2.1.5 Diluent in Accord with Compound
The diluent, whether liquid or gaseous, should be consistent with the chemical
compounds tested and not influence odor perception. For example, diluent air may be
filtered through activated carbon or be unfiltered room air. Liquid diluents include water,
diethyl phthalate, benzyl benzoate, and mineral oil. The selected diluent is determined by the
test purpose and practical considerations of the compound. Additionally, the relative
humidity of diluent air (or other inert gas) should be controlled at approximately 50%.
1.2.1.6 Presentation Mode That Minimizes Additional Dilution (Ambient) Ah* Intake
Vapors are inhaled from openings of varying size. Some of these allow ambient air to
be inspired along with the sample, thereby increasing the dilution factor by an unknown
amount. Common delivery systems are (1) nose ports held under the nostrils, (2) vents into
which the whole head is inserted, (3) flasks into which the nose is inserted, (4) syringes that
impinge vapor into the nose, and (5) whole rooms into which the odorant is injected. In
general, an opening that allows insertion of the nose or the whole head is desirable as it
reduces the intake of ambient air. Delivery systems that did not control the mixing of the
odorant with ambient air were not accepted.
1.2.1.7 Analytic Measurement of Odorant Concentration
The concentration of odorant as it reaches the panelist should be measured accurately.
The capability to measure concentration of some odorants has occurred only recently.
Therefore, a major problem with early threshold studies and a drawback of some modern
studies is the absence of such analytic devices.
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1.2.1.8 Calibration of Flow Rate and Face Velocity (for Olfactometers)
Important system calibrations include flow rate and face velocity. Flow rates on
individual olfactometers vary from 0.5 L/min to more than 9 L/min. This disparity in the
flow rate has been found to cause a fourfold difference in threshold values. Odorant flow
rate should be at approximately 3 L/min, although researchers differ in their opinion of a
"best" flow rate. Flow rate then becomes an important consideration in the critique. The
face velocity refers to the rate at which the odor is flowed at the panelist and should be
maintained at a flow barely perceptible by the panelist.
1.2.1.9 Consideration of Threshold Type (Detection or Recognition)
Thresholds may be either of two types, detection or recognition. The detection
threshold is defined as the lowest concentration at which a specified percentage of the panel
(usually 50%) detects a stimulus as being different from odor-free blanks. The recognition
threshold is the lowest odorant concentration at which a specified percentage of the panel
(again, usually 50% or the median) can ascribe a definite character to the odor. In general,
recognition thresholds are approximately two to ten times higher than detection thresholds
(Hellman and Small, 1974). The type of threshold measured is dependent on the test
purpose. For example, detection thresholds are of greater interest in basic research, while
recognition thresholds are of greater value to the food industry. Recognition and detection
thresholds are differentiated in this report.
1.2.1.10 Presentation Series That Reduces Olfactory Fatigue
Concentration presentation order is an important factor in the presentation method, as
olfactory adaptation occurs rapidly. After three minutes of exposure to an odorant, perceived
intensity is reduced about 75% (Bartoshuk and Cain, 1977). A common method to control
for this is to present concentrations in ascending order (from weaker to stronger
concentrations, or greater to lesser dilution) or to allow for long periods between
presentations. Descending and random presentation series do not control for adaptation
unless specific steps are taken to eliminate it. Recognizing the need to control for adaptation
in random or descending patterns of presentation, researchers apply various methods such as
presenting one concentration per day (Dixon and Ikels, 1977) or using different subjects at
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each concentration step (Gundlach and Kenway, 1939). Odor threshold determinations were
accepted only if the methods used controlled adequately for adaptation.
1.2.1.11 Repeated Trials
Individual test-retest reliability for threshold values is generally low (Punter, 1983) but
is dependent on the number of trials (Cain and Gent, 1991). Determinations should be
repeated for reliability. Additionally, computing the mean across panelists' scores will reduce
individual variability.
1.2.1.12 Forced-Choice Procedure
A forced-choice procedure minimizes anticipation effects for thresholds by eliminating
false positive responses. Panelists choose between the stimuli and one or two blanks.
Use of forced-choice procedures was not stringently applied as a criterion. An earlier
method, presenting a stimuli and blank as a paired comparison, was also included in this
category. Both methods reduce anticipation effects.
1.2.1.13 Concentration Step Increasing by a Factor of Two or Three
In determining odor threshold values, the odorant should be presented successively at
concentration intervals no more than three times the preceding one. Interval size is
determined by the range of sensitivity of the sample of panelists and by the number of
concentrations that can be analyzed in a given experiment. Smaller step size may result in
failure to identify the threshold for all panelists. Larger step size might result in a less
precise calculation of the average threshold because of the extrapolation over a greater range.
A 3-fold interval is selected as a maximum necessary to result in a useful dose-response.
1.2.2 Critique of Odor Threshold Measurement Techniques
Threshold compilations such as Van Gemert and Nettenbreijer (1977), Verschueren
(1977), and Fazzalari (1978) contain threshold values from sources published in the early
1900s and before. In some cases, reported threshold values vary by a factor of a million or
more for one compound. The reported values for n-butyl alcohol range from 1.8 X 10"4 to
1.45 X 10'7 g/L (Amoore and Hautala, 1983).
1-14
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The fact that threshold values and the methodology involved may vary widely has often
been recognized. Factors affecting threshold measurement (Punter, 1983) include stimuli
flow rate, olfactometric systems, age and type of panelist, instruction and threshold
procedure, and panelists' experimental experience.
Other important factors contributing to threshold value variability are the purity of the
chemical compound, the type of threshold (detection or recognition) determined, and the
stimulus itself (water vapor or gas vapor). These last two factors make the practice of
pooling thresholds questionable at best. Considering the sources of variability, it is
understandable that published threshold values differ.
References were reviewed for their overall adherence to experimental procedures that
address the response characteristics of the human olfactory system. The results of the
literature search and review are presented in tabular form in Section 2. The following are
included in Table 2-1.
• CAS RN (Chemical Abstracts Service registry number)
• Chemical name and some of its synonyms
• Chemical formula
• Molecular weight
• First author, date
• Odor threshold
• Type of threshold
• Geometric mean of critically acceptable odor threshold value
• Type of odor threshold represented by geometric mean
• Odor character
1-15
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1.3 ODOR THRESHOLDS IN RELATION TO RISK ASSESSMENT
The detection of chemical odors may trigger odor complaints that are associated with
safety concerns due to chemical exposure. The key questions regarding odor detection,
safety, and risk assessment are:
1. If a chemical odor is present, does that indicate a health risk?
2. If chemical odors are absent, does that signify an absence of health risk?
3. Does olfaction provide an adequate margin of safety by allowing detection of toxic
chemicals that prompts avoidance of exposure?
Knowledge of odor threshold values, together with a variety of background information,
toxicity data, and analytical data are necessary to answer these questions in specific situations.
1.3.1 Relationship Between Odor Threshold Values and Health-Based
Ambient Criteria
The relationship between odor threshold values and health-based exposure criteria (e.g.,
inhalation reference concentrations [RfCs] for noncancer endpoints, inhalation risk-specific
concentrations for cancer risk, acceptable ambient concentrations [AACs], occupational
exposure limits [OELs]) is an essential determinant of the usefulness of odor as an indicator
in a site evaluation. If the odor threshold value is lower than the ambient criteria, then
absence of odor may signify that the ambient concentration is below that which could produce
adverse health effects. In this case, detection of odor is not a sufficient indicator of whether
a health threat is posed because the ability of the sensory apparatus to quantify odor and thus
chemical exposure is very limited. Accurate methods of chemical quantification need to be
used to determine whether ambient concentrations are sufficient to pose a risk.
The converse of the above, cases in which the odor threshold value is greater than
health-based ambient criteria, present the opposite type of problem. In this case, odor is
useful as an indicator of potential harm since the detection of odor indicates chemical
concentrations in the potentially toxic range. However, a lack of odor does not necessarily
indicate absence of risk, since toxic effects can occur at chemical concentrations that are
below that perceptible by the nose. Here again, analytical chemistry is needed to ensure that
toxic levels of ambient contaminants are not present.
1-16
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Chemical mixtures can present odors that may or may not reflect the hazard potential of
the chemical constituents. For example, a highly odorous but relatively nontoxic chemical
may be present along with a nonodorous but highly toxic chemical. In this case, the odorous
chemical serves as a warning that the toxic chemical is present. However, there may be
instances in which the two chemicals become dissociated (aging of the mixture, in different
manufacturing or disposal processes, etc.); and judgments about the presence or absence of
the toxic component would be incorrect if they were based upon detection of the odorous
component. Therefore, assumptions about the relationship between odor and risk can only be
made for the specific circumstances in which chemical mixtures are found.
An exemplary study of complex mixtures and odor at an industrial site was that
performed for tar-contaminated soils at manufactured gas plants (Roberson et al., 1989). For
analysis of odors from complex mixtures, the odorous sample must be fractionated and
fractions characterized in terms of odor and chemical identity. In this case, the sample was
analyzed by gas chromatography with mass spectrometry (GC/MS) in such a way so that the
GC effluent was split delivering a portion to the MS and a portion to the odor scientist. This
enabled the odor associated with each component to be separately evaluated. Several
different types of soil contamination were evaluated in this way to describe the prevalent
odors and chemical constituents associated with different soil samples. Odor threshold values
were then compared to health-based ambient criteria to determine if odor detection would be
a suitable marker for elevated risks. The ambient criteria were threshold limit values (TLVs)
for workers and l/100th the TLV for a residential exposure limit. In their samples, odorous
components (thiophene, hydrogen sulfide, naphthalene) were detected in conjunction with
relatively nonodorous components (cycloalkanes, benzene), thus providing an applicable
signal for toxicant exposure. The authors concluded from this study that health risks were
unlikely where no odor is present, but analytical data are needed if odors can be detected.
Their conclusion, however, did not carefully consider the relative concentrations of odorous
vs. nonodorous/toxic components, in relation to differences between odor threshold values for
the odorous compounds and exposure limits for the most toxic compounds. Both the relative
quantities and the odor threshold-to-exposure limit ratios of all chemicals in the mixture must
be assessed before firm conclusions can be drawn. However, the study reported a fairly good
correlation between the perceived odor intensity and the measured levels of naphthalene, total
1-17
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polycyclic aromatic hydrocarbons, and total volatile organic compounds. Thus, in this case,
where odors were detected they were useful indices of exposure to toxic components.
These types of relationships between odor thresholds and health-based ambient criteria
are the basis for using odor as an indicator of toxicity and risk. However, as outlined below,
several additional factors must be taken into account when attempting to relate odor to risk.
1.3.1.1 Background Exposure
Continued exposure to odorous chemicals generally causes a decreased ability to smell
these chemicals. Therefore, if the background concentration in the vicinity of a source is
sufficient to cause a detectable odor, the odor threshold value for individuals in the affected
environment may be higher than that reported in the literature. If reported odor threshold
concentrations are lower than the ambient criteria, the desensitizing influence of background
exposure may narrow or eliminate the safety margin between the odor threshold concentration
and the ambient criteria. In this case, a previously unexposed person may be warned by
olfactory indicators from an episode of excessive chemical release, while a chronically
exposed person might not as readily detect the release and thus be at greater risk. Therefore,
to evaluate whether detection of a chemical via the sense of smell is a reasonable indicator of
risk, the ambient concentrations that the receptor is acclimated to must be known, together
with the chemical's ability to desensitize olfaction.
1.3.1.2 VariabUity in the Odor Threshold Data
As discussed in previous sections, the odor threshold literature for a particular chemical
can provide a wide range of threshold values. Often the disparity stems, in part, from
interindividual differences in olfaction, and in part, from methodological differences. A wide
range of odor thresholds presents a large degree of uncertainty regarding the threshold for a
particular individual. This diminishes the usefulness of the odor threshold for assessing
whether a margin of safety exists between it and the ambient criteria value. Further, the
variability decreases the usefulness of odor detection as an indicator of toxicant exposure.
Another related factor that governs the usefulness of the threshold data for risk
assessment is the type of threshold reported. While detection thresholds may be more
commonly reported, they are not as useful as recognition thresholds because simply detecting
1-18
-------
an olfaction stimulus may not be a sufficient warning of chemical exposure. Further, in
situations where numerous chemicals are present, a specific and characteristic odor may be
required to clearly indicate that a release above background has occurred. Therefore, the
utility of and margin of safety afforded by the threshold can be overestimated if the threshold
is for detection rather than recognition. However, in cases where individuals anticipate a
chemical exposure, odor detection may be a suitable signal to trigger a more extensive
investigation.
1.3.1.3 Choice of Health-Based Ambient Criteria
The ambient criteria used for comparison with odor threshold values can greatly affect
the interpretation of odor threshold value usefulness as an indicator of risk. Use of OELs
such as TLVs (American Conference of Governmental Industrial Hygienists, 1986),
permissible exposure limits (PELs), recommended exposure limits (RELs), or short-term
exposure limits (STELs) may be appropriate for the workplace.
However, these OELs are not considered to be protective of the general population,
which may receive continuous ambient exposure, and which may include more sensitive
individuals (e.g., young children, pregnant woman, the elderly). This has been addressed by
numerous states and localities in the form of AACs, which are potentially useful health-based
ambient criteria, especially because they have been developed for a large number of
chemicals.
Other types of health-based criteria are the inhalation RfC and the inhalation unit risk.
The RfC is an estimate (with uncertainty spanning perhaps an order of magnitude) of the
daily exposure to the human population (including sensitive subgroups) that is likely to be
without an appreciable risk of deleterious effects during a lifetime (U.S. Environmental
Protection Agency, 1990). The RfCs are developed by EPA, and values are verified by the
RfD/RfC Work Group, which affords a degree of oversight and standardization. The RfCs
are based upon available toxicity data (subchronic and chronic animal studies and
epidemiological studies) and are derived by dividing the highest concentration level at which
no adverse effects were seen (the NOAEL) by uncertainty factors to approximate, as
necessary, interspecies extrapolations, intraspecies variability, data base deficiencies,
extrapolation from subchronic to chronic effects, and extrapolation from a lowest observable
1-19
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adverse effect level (LOAEL) to a NOAEL. Uncertainty factors are applied to the exposure
concentration after calculation of the human equivalent concentration as described in U.S.
Environmental Protection Agency, (1990). The RfCs are based upon the most sensitive
toxicity endpoint, as determined by available data. If several reliable studies are available,
the RfC is based upon the study demonstrating effects at the lowest concentration. The RfC
values are available from EPA in online format (Integrated Risk Information System [IRIS],
U.S. Environmental Protection Agency, 1991).
The inhalation unit risk is the cancer risk level associated with a specific ambient
concentration. The U.S. EPA has derived these values and has normalized them to an
ambient concentration of 1 /ig/m3 (i.e., the risk per pg chemical/m3 air) assuming exposure
for a lifetime. To convert these values for use as health-based ambient criteria, the
concentration associated with a specific level of risk (e.g., 1 x 10"6) can be calculated by
dividing the target risk level by the unit risk factor. For example, the unit risk factor for
acrylonitrile is 6.8 x 10~5 per mg/m3 (U.S. Environmental Protection Agency, 1991) and the
ambient concentration associated with a 1 x 10"6 risk is 0.015 mg/m3, which conceivably
could be used as the health-based ambient criteria protective against cancer risk. The
inhalation unit risk factors available on IRIS have undergone a review and verification
process in the Carcinogen Risk Assessment Verification Endeavor Work Group, which
ensures that appropriate test data and standardized methods were used to derive the values.
The RfC values and inhalation unit risk factors are currently in preparation for the
189 listed chemicals. Many of the listed chemicals will not have verified inhalation RfC
values or unit risk factors, in large part due to the general lack of chronic toxicity studies
conducted by the inhalation route of exposure. Thus, the evaluation of the usefulness of odor
threshold values for risk assessment suffers from the relative lack of inhalation toxicology
data. However, detailed analysis of the toxicology data base development for RfC and unit
risk estimates is proceeding in EPA, as is the development of methods for risk assessment of
acute exposure. New inhalation studies, method development, or dose route extrapolation
will make possible the derivation of new ambient criteria for use in assessing the relationship
between odor and risk.
1-20
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1.3.2 Theoretical Considerations: Is There a Link Between Odor and
Toxicity?
Detection of chemical odors may raise health concerns due to the awareness of exposure
to chemicals. However, while odor itself is a signal of some type of exposure, it does not
necessarily indicate a potential health risk unless the detected chemical is identified, and its
toxicity is understood. Without this information, odor detection is not useful in risk
assessment. This is because the mechanisms that appear to be involved with odor detection
have very little to do with the mechanisms involved in chemical-induced toxicity and
carcinogenesis.
The mechanisms involved in toxic phenomena are likely to be quite specific and distinct
from those involved in olfaction. Although the toxic mechanisms for many agents require
further study, a unifying hypothesis for cytotoxicants and carcinogens is that highly reactive
species result from chemical entry into a cell (Coles, 1984; Vaca et al., 1988; Recknagel and
Glende, 1973). These species may be the parent molecule, metabolites, or endogeneous
molecules (e.g., superoxide, lipid peroxides), which become disproportionately numerous due
to xenobiotic influences on normal cellular functioning. These reactive species are typically
electrophiles or oxidants, which can then irreversibly bind to or denature tissue
macromolecules (DNA, protein) such that normal structure and function is lost. While many
exceptions to this mechanistic framework likely exist, key aspects of this hypothesis are
relevant for a wide variety of potent toxicants and carcinogens.
The major distinctions between toxicant and odorant mechanisms are site of action
(nasal olfactory epithelium for odorants; various organs for toxicants), type of receptor (odor
receptor for odorants; DNA, miscellaneous protein receptors, or oxidant systems for
toxicants), and the chemical requirements for efficacy. The key point is that odorants need
not be strong toxicants and toxicants need not be odorous, so that there is no rationale for
making assumptions about risk based solely upon odor perception. However, detection of
odor in combination with information regarding chemical identity and toxic potency can be
useful information, especially in those cases where the odor threshold concentration is known
and can be compared to health-based ambient criteria. Since odor threshold concentration
values are often imprecise and since they may not be relevant for a particular individual, it is
advisable to obtain quantitative analytical data in cases where unknown or suspicious odors
1-21
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are detected, or where potentially harmful chemical releases are suspected, even if no odors
are detected.
1.3.3 Conclusions
Odor thresholds can be useful as a screening level, semi-quantitative approach for
hazard identification in cases where:
1. The chemical identity of the odor is known or can reasonably be presumed;
2. Acute and chronic toxicity data are available and these data have been converted to
appropriate health-based ambient criteria; and
3. The odor threshold data is not highly uncertain (i.e., reliable measurements of odor
threshold fall within an order of magnitude range).
In these cases, Table 1-1 applies. If the odor threshold is above the threshold for toxic
effects or safety concerns and an odor is detected, then cessation of exposure is prudent until
further testing can be done. Conversely, if the odor threshold is clearly below the toxicity
threshold and no odors are detected, then there is no immediate cause for concern. In cases
where the odor threshold is similar to or greater than the ambient criteria, the absence of odor
is not informative. Further, when the odor threshold is less than or similar to the ambient
criteria and odor is detected, the hazard potential cannot be evaluated without analytical data.
Although the detection of odor does not necessarily indicate risk in these cases, it does
indicate a chemical exposure that should be analyzed and quantified.
TABLE 1-1. RELATIONSHIP BETWEEN ODOR THRESHOLD VALUES
AND AMBIENT CRITERIA
No odor
Odor detected
Odor
Threshold Below
Ambient Criteria
Low level of
concern
Analytical data
required
Odor
Threshold ~ Ambient
Criteria
Analytical data
required
Analytical data
required
Odor
Threshold Above
Ambient Criteria
Analytical data
required
High level of
concern
1-22
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1.4 LITERATURE SEARCH AND REVIEW
1.4.1 Critiqued Odor Threshold Values
The literature search consisted of a review of odor threshold compilations that were
prepared by Van Gemert (1982), Van Gemert and Nettenbreijer (1977), Stahl (1973),
Fazzalari (1978), and the American Industrial Hygiene Association (1989). The original
references were then located if possible and reviewed based on the criteria discussed in
Section 1.2.1. Those references that were accepted are listed in Table 2-1 and coded with an
"A" next to the author's name.
The critiqued references and the odor threshold values are presented in Table 2-1.
Threshold methodologies are evaluated according to each of the thirteen criteria discussed in
Section 1.2.1. The geometric mean value, based on all accepted values, or recommended
best estimate for the odor threshold for each of the compounds is given in Table 2-1. This is
a common practice in sensory evaluation, as it accounts for the wide range of response over
several orders of magnitude. The means were rounded off to two significant digits. Where
values were given as a range, the geometric mean of the two points was taken for the
threshold.
In some cases, the mean value for detection is higher than the mean value for
recognition. This is a result of pooling of several data sets for the geometric mean.
Odor character descriptors in Table 2-1 are based on reports in the literature and
experience in odor investigation. The intensity level at which the character is determined is
seldom given in the sources reviewed. Since odor character can change with intensity, it
should be remembered that the character reported may differ from source to source. The
purpose here is to include an observation on the odorant character to accompany the threshold
value.
1-23
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2. ODOR THRESHOLD DATA FOR INDIVIDUAL
CHEMICALS AND CHEMICAL CATEGORIES
Table 2-1 summarizes all published odor thresholds for the 189 hazardous air pollutants
found to have reported odor thresholds. Chemicals are listed alphabetically. There are two
sets of entries for each chemical: Phase I Unreviewed Sources and Phase II Critiqued
Sources. Under the former are presented odor threshold values from sources that either were
rejected or were not reviewed. Under the latter are presented odor threshold values from
primary experimental sources that were critiqued. The table provides the following
information.
• CAS number
• Chemical name and synonyms
• Chemical formula
• Molecular weight
• Last name of the first author listed for the source
• Source code: A Accepted value based on critique
B Rejected value based on criteria
Bl Rejected value—water threshold
B2 Rejected value—minimum perceptible value
B3 Rejected value—water threshold/air conversion
B4 Rejected value—intensity
B5 Rejected value—insufficient methodology
Cl Rejected source based on review—secondary source
C2 Rejected source—incidental reference
C3 Rejected source—passive exposure/workplace
C4 Rejected source—passive exposure/experiment
Dl Omitted source—unpublished data
D2 Omitted source—personal communication
D3 Omitted source—anonymous reference
D4 Omitted source—omitted in Gemert
D5 Omitted source—pre-1900 reference
El Source located but not reviewed
E2 Source not located
2-1
-------
• Odor threshold values in milligrams per cubic meter (mg/m3) and parts per million
(ppm)
• Type of threshold: d = detection, r = recognition, ng = not given
• Geometric mean odor threshold
• Type of geometric mean threshold: d = detection, r = recognition
• Odor characteristic
2-2
-------
TABLE 2-1. REPORTED ODOR THRESHOLDS FROM ALL SOURCES
CAS # Compound Name Synonyms Formula M.W. Source
75070 Acetaldehyde C2H4° 44.05 Unreviewed Sources
Ethanal Zwaardemaker
(1914)
Backman (1917)
Takhirov (1974)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Pliska and Janicek
(1965)
Katz and Talbert
(1930)
Gofmekler (1967)
Leonardos et al.
(1969)
Hartung et al. (1971)
60355 Acetamide CH3CONH2 59.07 Unreviewed Sources
Acetic Acid Amide Backman (1917)
Ethanamide Critiqued Sources
No A or B Codes
75058 Acetonitrile C2HjN 41.05 Unreviewed Sources
Methyl Cyanide No C-E Codes
Ethanenitrile Critiqued Sources
Pozzani et al. (1959)
Dravnieks (1974)
Code
E2
El
El
D3
D3
B
A
B2
B
B5
El
-
-
A
A
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
mg/m ppm Threshold (ppm) Threshold Characteristic
0.7
0.062-0.075
0.49
0.0027
0.027
1,800
0.12
0.012
0.38
0.005
140-160
-
-
<67
1,950
0.39
0.034-0.042
0.27
0.0015
0.015
1,000
0.067
0.0067
0.21
0.0028
58-66
-
-
<40
1,161
0.067 d Pungent/fruity
d
r
ng
d
r
ng
d
d
r
ng
None Mousy
r
-
1,611 d Etherish,
aromatic
ng
d
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
Odor Thresholds
CAS#
98862
53963
107028
79061
Compound Name Synonyms
Acetophenone
Acetylbenzene
Methyl Phenyl Ketone
2-Acetylaminofluorene
2-Acetamidofluorene
Acrolein
2-Propenal
Acrylaldehyde
Acrylamide
Acrylic Amide
Ethylenecarboxamide
Formula M.W. Source
CgHjCOCHg 120.2 Unreviewed Sources
Gavaudan and
Poussel (1966)
Critiqued Sources
Imasheva (1963)
Tkach (1965)
Korneev (1965)
Hellman and Small
(1974)
Hellman and Small
(1974)
CjjHj3NO 223.3 No sources found
CjH^O 56.06 Unreviewed Sources
Buchberg et al.
(1961)
Knuth (1973)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Katz and Talbert
(1930)
Plotnikova (1957)
Leonardos et al.
(1969)
Sinkuvene (1970)
Cormack et al.
(1974)
CH2CHCONH2 71.08 No sources found
Code
El
B2
B2
B2
A
A
E2
D2
D3
D3
A
B2
B
B2
B
mg/m
0.23
0.01
0.01
0.01
1.5
2.9
0.2-0.7
0.14
0.069
0.32
4.1
0.8
0.48
0.07
0.23
ppm
0.047
0.002
0.002
0.002
0.3
0.6
0.087-0.31
0.061
0.03
0.14
1.8
0.35
0.21
0.031
0.1
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
0.3 d Sweet/almond,
0.6 r pleasant
ng
ng
ng
ng
d
r
1.8 d Pungent,
choking
ng
ng
d
r
ng
ng
r
ng
ng
Odorless
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
CAS # Compound Name Synonyms Formula M.W. Source Code mg/m ppm Threshold (ppm) Threshold Characteristic
79107 Acrylic Acid
Glacial Acrylic Acid
2-Propenoic Acid
Propenoic Acid
Vinyl Formic Acid
Acroleaic Acid
Propenoic Acid
Ethylene Carboxylic Acid
107131 Acrylonitrile
Vinyl Cyanide
2-Propenenitrile
107051 Ally [Chloride
3-Chloro- 1 -propene
3-Chloropropene
92671 4-Aminobiphenyl
p-Aminobiphenyl
Diphenylamine
C3H4O2 72.06 Unreviewed Sources 0.092 d Rancid/plastic/
No C-E Codes - - - ' -1.0 r sweet/acrid
Critiqued Sources
Hellman and Small
(1974) A 0.27 0.092 d
Hellman and Small
(1974) A3 1 r
C3H3N 53.06 Unreviewed Sources 1.6 d Onion/garlic,
No C-E Codes - - - - mild
Critiqued Sources
Stalker (1963) A 3.4 1.6 d
Leonardos et al.
(1969) B 47 22 r
CjH^Cl 76.53 Unreviewed Sources None Pungent,
Shell Chemical unpleasant
Corporation (1958) Cl 9.3-18.6 3.0-5.9 ng
Torkelson et al. ng
(1959) C4 3-9 1-3
Critiqued Sources
Leonardos et al. r
(1969) B 1.5 0.48
C12H11N 169-2 Unreviewed Sources None
Backman (1917) El 0.15-0.17 0.022-0.025 r
Critiqued Sources
No A or B Codes - -
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
s
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds
CAS # Compound Name Synonyms
62533 Aniline
90040 o-Anisidine
1332214 Asbestos
Formula M.W. Source
CgHjNI^ 93.12 Unreviewed Sources
Tempelaar (1913)
Huijer (1917)
Backman (1917)
Geier (1936)
Geier (1936)
Critiqued Sources
Jacobson et al.
(1958)
Tkachev (1963)
Leonardos et al.
(1969)
C?H9NO 123.2 No Sources Found
Magnesium No Sources Found
and/or Iron
Silicate Fibers
Code
E2
E2
El
E2
E2
A
B2
B
mg/m
0.97
0.046
5.0-5.8
1.2-1.5
2.0-2.5
38
0.37
3.8
ppm
0.25
0.012
1.3-1.5
0.32-0.39
0.53-0.66
10
0.097
1
Type of Threshold
Threshold (ppm)
10
d
d
r
d
r
ng
ng
r
Type of Odor
Threshold Characteristic
ng Pungent/oily,
characteristic
Odorless
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
Odor Thresholds
CAS # Compound Name Synonyms Formula M.W. Source
71432 Benzene C6H6 78p11 Unreviewed Sources
Backman (1917)
Backman (1918)
Grijns (1919)
Schley (1934)
Schley (1934)
Deadman and Prigg
(1959)
Koster (1971)
Naus (1962)
Critiqued Sources
Jones (1954)
Jones (1955)
Novikov (1957)
Gusev (1965)
May (1966)
May (1966)
Elfimova (1966)
Leonardos et al.
(1969)
Alibaev (1970)
Dravnieks and
O'Donnell (1971)
Laffort and
Dravnieks (1973)
Dravnieks (1974)
Punter (1980)
92875 Benzidine C12H12N2 184'2 No Sources F°"nd
4,4'-Bianiline
p,p'-Bianiline
4,4'-Biphenyldiamine
Code
El
E2
E2
E2
E2
E2
E2
Cl
B
B
B2
B2
A
A
B5
B
B2
B5
B
A
A
o
mg/m
6.6-6.9
5.3
420
8.8
12
9
37
6
480-510
180
4.9
2.8-4.0
180
310
2.5
15
2.9
38
14.5
380
108
ppm
2.1-2.2
1.7
131
2.8
3.8
2.8
12
1.9
150-160
56
1.5
0.88-1.3
56
97
0.78
4.7
0.91
12
4.5
119
34
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
61 d Aromatic/
r 97 r sweet/solvent
ng
ng
d
r
d
d
d
r
d
ng
ng
d
r
ng
r
ng
ng
ng
d
d
98077 Benzotrichloride
Benzenyl Chloride
Benzotrichloride
Benzenyl Trichloride
Benzylidyne Chloride
C6H5CC13
195.5 No Sources Found
Penetrating
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
oo
CAS #
100447
92524
117817
542881
75252
Compound Name Synonyms
Benzyl Chloride
alpha-Chlorotoluene
Biphenyl
Phenylbenzene
Bis(2-ethylhexyl) Phthalate (DEHP)
Bis(2-ethylhexyl)phthalate
Phthalic Acid, bis(2-ethylhexyl)ester
Bis(chloromethyl)ether
Chloromethyl Ether
Dichlorodimethyl Ether
Bromoform
Tribromomethane
Odor Thresholds
Formula M.W. Source Code mg/m ppm
C7HyCl 126.58 Unreviewed Sources
No C-E Codes
Critiqued Sources
Katz and Talbert
(1930) A 0.21 0.041
Leonardos et al.
(1969) B 0.24 0.046
Cj2Hj0 154.21 Unreviewed Sources
No C-E Codes
Critiqued Sources
Solomin (1961) B2 0.06 0.0095
C24H38°4 390.6 No Sources Found
(CH2C1)O(CH2C1) 115 No Sources Found
CHBrg 252.75 Unreviewed Sources
Passy (1893) D5 2-5 0.19-0,48
Backman (1917) El 2.2-2.5 0.21-0.24
Grijns(1919) E2 150 15
Rocen(1920) E2 30 2.9
Critiqued Sources
No A or B Codes - -
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
0.041 ng Pungent
-
r
None Pleasant/
butter-like
None Chloroform/
d sweet/
r suffocating
ng
r
-
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
K>
Odor Thresholds
CAS#
106990
156627
105602
133062
63252
75150
Compound Name Synonyms
1 ,3-Butadiene
Butadiene
Divinyl
Biethylene
Erythrene
Calcium Cyanamide
Calcium Carbamide
Caprolactam
6-Aminohexanoic Acid
6-Aminohexanoic Acid Lactam
Captan
Carbaryl
Carbon Disulfide
Formula M.W. Source
C^Hg 54.09 Unreviewed Sources
Deadman and
Prigg (1959)
Jeltes (1975)
Critiqued Sources
Mullins (1955)
Ripp (1968)
Laffort and
Dravnieks (1973)
Hellman and Small
(1974)
Hellman and Small
(1974)
CaCN2 80.1 No Sources Found
CgHjjON 113.2 Unreviewed Sources
No C-E Codes
Critiqued Sources
Krichevskaya (1968)
C9H802SNCI3 300.6 No Sources Found
C12H11NO2 201.2 No Sources Found
C$2 76.13 Unreviewed Sources
Deadman and Prigg
(1959)
Frantikova (1962)
Critiqued Sources
Hildenskiold (1959)
Baikov (1963)
Leonardos et al.
(1969)
Code
E2
E2
B5
B2
B
A
A
-
B2
E2
E2
B2
B2
B
mg/m
2.1
0.22
169
4
5.8
1
2.4
-
0.3
0.07
1.3
0.05
0.08-0.5
0.65
ppm
0.95
0.099
76
1.8
2.6
0.45
1.1
-
0.065
0.022
0.42
0.016
0.026-0.16
0.21
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
0.45 d Aromatic/
1.1 r rubber, mild
d
ng
r
ng
ng
d
r
None
-
ng
Slightly
pungent
None Vegetable
sulfide/
d medicinal
ng
ng
ng
r
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
I—i
o
Odor Thresholds
CAS #
56235
463581
120809
133904
57749
Compound Name Synonyms
Carbon Tetrachloride
Tetrachloromethane
Perchloromethane
Benzinoform
Carbonyl Sulfide
Carbon Oxysuliide
Carbonyl Oxysulfide
Catechol
1 ,2-Benzenediol
2-Hydroxyphenol
Chloramben
Chlordane
1,2,3,4,5,6,7, 8,8-octachloro-
2,3,3a,4,7,7a-hexahydro-4,7-
methano- 1 H-indene
Formula M.W. Source
CC14 153.82 Unreviewed Sources
Lehmann and
Schmidt-Kehl (1936)
Davis (1934)
Critiqued Sources
Allison and Katz
(1919)
May (1966)
May (1966)
Leonardos et al.
(1969)
Belkov (1969)
Nikiforov (1970)
Dravnieks (1974)
Punter (1980)
COS 60.07 Unreviewed Sources
No C-E Codes
Critiqued Sources
Polgar et al. (1975)
CgHgO2 110.1 No Sources Found
C7H5NO2C12 206 No Sources Found
Cj0HgC|g 409.8 No Sources Found
Code
El
Cl
B5
A
A
B
B5
B5
A
A
-
A
mg/m
900
500
4,533
1,260
1,600
135-630
11.5-58
10.58
3,700
884
-
0.25
ppm
143
79
720
200
250
21-100
1.8-9.0
1.68
588
141
-
0.1
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
255* d Sweet/dry/
250 r cleaner,
ng distinctive
ng
ng
d
r
r
ng
ng
d
d
0.1 ng sulfide
-
ng
Odorless
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
N>
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds
CAS # Compound Name Synonyms Formula M.W. Source
7782505 Chlorine Cl 35.45 Unreviewed Sources
Fieldner et al. (1921)
Smolczyk and Cobler
(1930)
Styazhkin (1963)
Rupp and Henschler
(1967)
Rupp and Henschler
(1967)
Kramer (1976)
Critiqued Sources
Takhiroff(1957)
Leonardos et al.
(1969)
Dixon and Ikels
(1977)
79118 Chloroacetic Acid C2H3C1O2 94.5 Unreviewed Sources
Backman (1917)
Critiqued Sources
Smith and
Hochstettler (1969)
532274 2-Chloroacetophenone CgHyCIO 154.6 Unreviewed Sources
Phenyl Chlrormethyl Ketone No C-E Codes
Phenacyl Chloride Critiqued Sources
Katz and Talbert
(1930)
108907 Chlorobenzene C6H5C1 112.56 Unreviewed Sources
Monochlorobenzene Backman (1917)
Critiqued Sources
Mateson (1955)
Tarkhova (1965)
Leonardos et al.
(1969)
Smith and
Hochstettler (1969)
Punter (1980)
Code
Cl
E2
E2
C4
C4
D2
B2
B
A
El
B
-
A
El
B5
B2
B
B
A
mg/m
10
1.43-14.3
0.7
0.06-0.15
0.3
3.2-7.8
0.8
0.6
0.23
0.6
0.05
-
0.1-0.7
7.5-8.1
21.6
0.4
0.97
3
5.9
ppm
6.9
0.99-9.9
0.48
0.041-0.1
0.2
0.21-5.38
0.55
0.41
0.16
0.19
0.02
-
0.02-0.11
1.6-1.8
4.7
0.087
0.21
0.65
1.3
Type of Threshold
Threshold (ppm)
0.16
ng
ng
ng
d
r
ng
ng
r
d
None
r
r
0.07
-
ng
1.3
r
ng
ng
r
r
d
Type of Odor
Threshold Characteristic
d Suffocating/
sharp /bleach
ng Penetrating
odor similar to
vinegar
ng Pungent/floral
d Almond-like/
shoe polish
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
I
h—'
K>
Odor Thresholds
CAS # Compound Name Synonyms
510156 Chlorobenzilate
67663 Chloroform
Trichloromethane
107302 Chloromethyl Methyl Ether
126998 Chloroprene
2-Chloro-l ,3-butadiene
1319773 Cresols (isomers and mixtures)
Cresylic Acid
See o-Cresol
See m-Cresol
See p-Cresol
Formula M.W. Source
C16H14C12°3 325-2 No Sources Found
CHCI3 119.4 Unreviewed Sources
Passy (1893)
Tempelaar (1913)
Backman (1917)
Grijns (1919)
Rocen (1920)
Rocen (1920)
Mitsumoto (1926)
Schley (1934)
Schley (1934)
Morimura (1934)
Lehmann and
Schmidt-Kehl (1936)
Janicek et al. (1960)
Naus (1962)
Critiqued Sources
Allison and Katz
(1919)
Scherberger et al.
(1958)
Dravnieks (1974)
Punter (1980)
No Sources Found
C4H5C1 88.54 Unreviewed Sources
Nystrom (1948)
Critiqued Sources
Mnatsakanyan
(1962)
Code
D5
E2
El
E2
E2
E2
El
E2
E2
El
El
El
Cl
B5
B
A
A
Cl
B
mg/m
30
3,000
14.1-15.1
2,350
730
2,500
353.8-589
42
56
480-622
1,000-1,500
3,700
3
3,300
6,900
1,350
650
500-1,000
0.4-2.0
ppm
6.1
614
2.9-3.1
481
150
512
72.5-121
8.6
11
98-127
205-307
758
0.6
676
1,413
276
133
138.1-276.1
0.11-0.55
Geometric
Mean
Air Odor
Type of Threshold
Threshold (ppm)
192
d
d
r
ng
d
r
r
d
r
r
ng
ng
d
ng
r
d
d
None
r
ng
Geometric
Mean
Air Odor
Type of Odor
Threshold Characteristic
d Sweet/
suffocating
characteristic
Irritating
Rubber
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
t-O
CAS # Compound Name Synonyms Formula M.W. Source
95487 o-Cresol CyHgO 108.1 Unreviewed Sources
o-Cresylic Acid Backman (1917)
2-Methylphenol Stuiver (1958)
Kendall et al.
(1968)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
No A or B Codes
108934 m-Cresol C7H8° 1Q&.1 Unreviewed Sources
3-Methylphenol Backman (1917)
Stuiver (1958)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Nader (1958)
106445 p-Cresol C7HgO 108.1 Unreviewed Sources
p-Hydroxytoluene Backman (1917)
4-Methylphenol Baldus (1936)
Baldus (1936)
Stuiver (1958)
Punter (1975, 1979)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Leonardos et al.
(1969)
Code
El
E2
E2
D3
D3
-
El
E2
D3
D3
A
El
E2
E2
E2
D1.D2
D3
D3
B
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
mg/m ppm Threshold (ppm) Threshold Characteristic
0.004
0.0004
0.0028
0.0017
0.027
-
0.0007-0.0009
0.0004
0.00057
0.011
0.00022-.035
0.03-0.04
0.0125
0.015
0.00005
0.024
0.00018
0.0084
0.0044
0.0009
0.00009
0.00063
0.00038
0.0061
-
0.00016-0.00020
0.00009
0.00013
0.0025
0.000050-0.0079
0.0068-0.0090
0.0028
0.0034
0.000011
0.0054
0.000041
0.0019
0.00099
None Phenolic,
r tarry
d
r
d
r
-
0.004 d Phenolic
r
d
d
r
ng
None Phenolic
r
d
r
d
d
d
r
r
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
CAS#
98828
94757
72559
334883
132649
96128
84742
106467
Compound Name Synonyms
Cumene
Isopropylbenzene
2,4-D, Salts and Esters
2,4-Dichlorophenoxyacetic Acid
DDE
Dichlorodiphenyldichloroethylene
Diazomethane
Dibenzofuran
Diphenylene Oxide
1 ,2-Dibromo-3-chloropropane
Dibutylphthalate
p-Dichlorobenzene
1 ,4-Dichlorobenzene
Odor Thresholds
Formula M.W. Source Code mg/m ppm
Cc)Hj2 120.2 Unreviewed Sources
Koster(1971) E2 0.25 0.051
Anonymous (1980) D3 0.074 0.015
Anonymous (1980) D3 0.54 0.11
Critiqued Sources
Solomin (1964) B2 0.06 0.012
Elfimova (1966) B5 0.025 0.0051
Turk (1973) B 4.8-6.4 0.98-1.3
Hellman and Small
(1974) A 0.04 0.008
Hellman and Small
(1974) A 0.23 0.047
Punter (1980) A .65 0.132
CgHgCl2O3 221 No Sources Found
(CiCgH^iCC^ No Sources Found
CH2N2 42.04 No Sources Found
C12HgO 168.2 No Sources Found
CjH^B^Cl 236.3 Unreviewed Sources
Torkelson and Rowe
(1981) Cl 0.1-0.3 0.01-0.03
Critiqued Sources
No A or B Codes -
C6H4 278.3 No Sources Found
(COOC4H9)2
CgH4Cl2 147 Unreviewed Sources
Hollingsworth et al.
(1956) C3 <90 <15
Critiqued Sources
Punter (1980) A 0.73 0.121
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
0.032 d Sharp
d 0.047 r
d
r
ng
ng
r
d
r
d
None
ng
-
Slightly ester
0.12 d Camphor/
mothballs,
ng penetrating
d
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
CAS#
91941
111444
542756
Compound Name Synonyms Formula
3,3'-Dichlorobenzidine Cj^H^Cl^N
Dichloroethyl Ether C^HoCUO
Bis(2-chloroethyl) Ether
1,3-Dichloropropene CoH^CU
1 ,3-Dichloropropylene
3-Chloroallyl Chloride
3-Chloropropenyl Chloride
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
M.W. Source Code mg/m3 ppm Threshold (ppm) Threshold Characteristic
2 253.1 No Sources Found
143 No Sources Found Sweet, like
chloroform
111 No Sources Found
62737 Dichlorvos
2,2 Dichloroethenyl Dimethyl
Phosphate
2,2 Dichlorovinyl Dimethyl Phosphate
Phosphoric Acid, 2,2-Dichloroethenyl
Dimethyl Ester
Phosphoric Acid, 2,2-Dichlorovinyl
Dimethyl Ester
221 No Sources Found
111422
64675
121697
Diethanolamine
3-Azapentane-l ,5-Diol
2,2 Dihydroxydiethylamine
Diethyl Sulfate
Diethyl Sulphate
Ethyl Sulfate
Sulfuric Acid, Diethyl Esters
Dimethylaniline
N,N-Dimethylaniline
N,N-Diethyl Aniline
C4HjjNO2 105.1 Unreviewed Sources None
England et al.
(1978) E2 1.2 0.28 r
Critiqued Sources
No A or B Codes - -
C4Hj0SO4 154.2 No Sources Found Faint,
ethereal,
irritating after-
effect
CgHjjN 121.2 Unreviewed Sources None Oily
Backman (1917) El 0.8-1.0 0.16-0.20 r
Geier(1936) E2 0.005-0.1 0.0010- d
Geier(1936) E2 0.05-0.25 0.020 r
Deadman and 0.010-0.050
Prigg (1959) E2 0.012 d
Critiqued Sources 0.0024
No A or B Codes - -
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
t—L
ON
CAS#
119904
60117
119937
68122
57147
131113
77781
Compound Name Synonyms
3 ,3-Dimethoxybenzidine
Dianisidine
Dimethyl aminoazobenzene
Benzenamine,
N , N-dimethy l-4-(pheny lazo)
p-(Dimethylamino) Azobenzene
4-(N , N-Dimethylamino)azobenzene
3, 3 '-Dimethyl Benzidine
Dimethyl Carbamoyl Chloride
Carbamic Chloride, Dimethyl
Dimethylcarbaminc Acid Chloride
Dimethylcarbamidoyl Chloride
Dimethylcarbamyl Chloride
Dimethylchloroformamide
Ortho-Tolidine
Dimethyl Formamide
N,N-Dimethyl Formamide
DMF
1 , 1 -Dimethylhydrazine
N,N-Dimethylhydrazine
unsym-Dimethylhydrazine
Dimethyl Phthalate
Dimethyl Sulfate
Sulfiiric Acid, Dimethyl Ester
Odor Thresholds
•5
Formula M.W. Source Code mg/m ppm
C14H16N2°2 244'3 No Sources Found
Cj^HjjNj 225.3 No Sources Found
C14H16N2 212.3 No Sources Found
C3H7ON 73.09 Unreviewed Sources
No C-E Codes
Critiqued Sources
Odoshashvili (1962) B2 0.14 0.047
Leonardos et al.
(1969) B 300 100
C2HgN2 60.1 Unreviewed Sources
Rumsey and Cesta
(1970) C3 <0.75 <0.31
Critiqued Sources
Jacobson et al.
(1955) A 15-35 6.1-14
C10H10°4 194.2 No Sources Found
C2HgO4 102.1 No Sources Found
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
None Fishy
ng
r
10 Fishy/ammonia
ng
ng
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
K)
CAS#
534521
51285
121142
123911
122667
106898
106887
Compound Name Synonyms
4,6-Dinitro-o-cresol, and Salts
4 ,6-Dinitro-2-methy Iphenol
2,4-Dinitrophenol
2,4-Dinitrotoluene
Dioxane
1,4-Diethylene Dioxide
1,4-Dioxane
Diethylene Oxide
Dioxyethylene Ether
1 ,4-Diethyleneoxide
1 ,2-Diphenylhydrazine
Epichlorohydrin
l-Chloro-2,3-epoxypropane
Glycidyl Chloride
3-Chloropropene-l ,2-oxide
1 ,2-Epoxybutane
1,2-Butylene Oxide
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
Formula M.W. Source Code mg/m ppm Threshold (ppm) Threshold Characteristic
C7H6N2°5 198-1 Unreviewed Sources
Kurtschatowa and None
Dawidkowa (1970) E2 0.004-0.021 0.0005-0.0026 ng
Critiqued Sources
No A or B Codes
CgH^j^Oj 184.1 No Sources Found Sweet, musty
C7H6N2O4 182.1 No Sources Found
C4HgO2 88.1 Unreviewed Sources 22* d Sweet/mild,
Roster (1971) E2 45-9,400 12-2,609 d 22 r alcohol/
Wirth and Klimmer ethereal
(1937) Cl 10 2.8 d
Critiqued Sources
May (1966) A 620 172 d
May (1966) A 1,000 278
Hellman and Small r
(1973, 1974) A 2.9 0.8
Hellman and Small d
(1973, 1974) A 6.5 1.8
Dravnieks (1974) A 270 75 r
d
C12H12N2 184-2 No Sources Found
C-jHijCIO 92.53 Unreviewed Sources None Chloroform,
Shell Chemical pungent,
Corporation (1959) Cl 38-46 10-12 ng garlic,
Critiqued Sources sweet
Fomin (1966) B2 0.3 0.08 ng
C4HgO 72.12 No Sources Found
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
CAS # Compound Name Synonyms
140885 Ethyl Acrylate
Ethyl 2-Propenoate
100414 Ethyl Benzene
Phenylethane
K)
OO 51796 Ethyl Carbamate
Urethane
75003 Ethyl Chloride
Chloroethane
106934 Ethylene Dibromide
Dibromoethane
Formula M.W. Source Code mg/m
CjHgC^ 100.1 Unreviewed Sources
Anonymous (1980) D3 0.00082
Anonymous (1980) D3 0.0053
Critiqued Sources
Leonardos et al.
(1969) B 0.0019
Hellman and Small
(1973, 1974) A 0.001
Hellman and Small
(1973, 1974) A 0.0015
CgHjQ 106.2 Unreviewed Sources
Roster (1971) E2 0.4
Critiqued Sources
Ivanov (1964) B2 2.0-2.6
C3H7NO2 89.1 No Sources Found
C2HjCl 64.52 No Sources Found
BrCH2CH2Br 187.9 No Sources Found
ppm Threshold (ppm) Threshold Characteristic
0.00024 d Sweet/ester/
0.0002 d 0.00037 r plastic
0.0013 r
0.00046 r
0.00024 d
0.00037 r
None Oily/solvent,
0.092 d aromatic
0.46-0.60 ng
Odorless
Etherial,
pungent
Sweet
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds
CAS#
107062
107211
151564
75218
96457
75343
Compound Name Synonyms
Ethylene Dichloride
1 ,2-Dichloroethane
Ethylene Chloride
Ethylene Glycol
Ethylenimine
Dimethylenimine
Aziridine
Ethylene Oxide
Oxitane
1 ,2-Epoxyethane
Ethylene Thiourea
1 , 1 -Dichloroethane
Formula M.W. Source
CjH^C^ 98.96 Unrcviewed Sources
McCawley (1942)
Irish (1963)
Critiqued Sources
Jones (1955)
Borisova (1957)
Scherberger et al.
(1958)
May (1966)
May (1966)
Dravnieks and
O'Donnell (1971)
Hellman and Small
(1974)
Hellman and Small
(1974)
C2HgO2 62.07 No Sources Found
C2H5N 43 .07 Unreviewed Sources
Carpenter et al.
(1948)
Critiqued Sources
Berzins (1968)
C2H4O 44.05 Unreviewed Sources
No C-E Codes
Critiqued Sources
Jacobson et al.
(1956)
Yuldashev (1965)
Hellman and Small
(1974)
Hellman and Small
(1974)
C3H6N2S 102.1 No Sources Found
C2H4C12 98.97 No Sources Found
Code
E2
Cl
B
B2
B
A
A
B5
A
A
C4
B5
-
A
B2
A
A
mg/m
1,200-4,000
200
1,500
1.75-23.2
820
450
750
190
25
165
3.6
1.25-3.5
-
1,260
1.5
470
900
ppm
297-988
49
371
4.3-5.7
203
111
185
47
6
41
2
0.71-2.0
-
690
0.82
257
493
Type of Threshold
Threshold (ppm)
26
ng 87
ng
d
ng
r
d
r
ng
d
r
None
ng
ng
257
493
ng
ng
d
r
Type of Odor
Threshold Characteristic
d Chloroform
r
Odorless
Ammonia
d Sweet/olefinic
r
Faint ammonia
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
N)
to
o
Geometric
Mean
Air Odor
Odor Thresholds Type of Threshold
CAS#
50000
76448
118741
87683
77474
67721
822060
680319
Compound Name Synonyms
Formaldehyde
Methanal
Heptachlor
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Perchlorocyclopentadiene
Hexacloroethane
Hexamethylene- 1 ,6-diisocyanate
Hexamethylphosphoramide
Hempa
Formula M.W. Source
CH2O 30.03 Unreviewed Sources
Backman (1917)
Buchberg et al.
(1961)
Takhirov (1974)
Makeicheva (1978)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Melekhina (1958)
Pliska and Janicek
(1965)
Sgibnev (1968)
Leonardos et al.
(1969)
Fel'dman and
Bonasheuskaya
(1971)
CjQHyCly 375.3 No Sources Found
CgClg 284.8 No Sources Found
C4Clg 260.8 No Sources Found
C5Clg 272.8 Unreviewed Sources
Treon et al. (1955)
Critiqued Sources
No A or B Codes
C2C16 236.7 No Sources Found
CgHj2N2O2 168.2 No Sources Found
CgH18N3PO 179.2 No Sources Found
Code
El
E2
El
El
D3
D3
B2
B
B2
B
B2
C2
-
mg/m
0.033-0.036
1.1-2.2
0.065
0.077
0.49
2.3
0.07
12,000
0.3-0.4
1.2
0.073
1.7
-
ppm Threshold (ppm)
None
0.027-0.029 r
0.90-1.8 ng
0.053 ng
0.063 ng
0.4 d
1.9 r
0.057 ng
9,770 ng
0.24-0.33 ng
0.98 r
0.059 ng
None
0.15 ng
-
Geometric
Mean
Air Odor
Type of Odor
Threshold Characteristic
Pungent/strong
Mild
Harsh, pungent
Camphor-like
Mild, ammonia
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
Odor Thresholds
CAS # Compound Name Synonyms Formula
110543 Hexane C6H14
n-Hexane
302012 Hydrazine N2H4
7647010 Hydrogen Chloride HC1
Hydrochloric Acid
7664393 Hydrogen Fluoride HF
Hydrofluoric Acid
123319 Hydroquinone C6H6°2
78591 Isophorone C9H14O
3,5,5-Trimethyl-2-cyclohexenone
M.W. Source
86.17 Unreviewed Sources
Patty and Yant
(1929)
Critiqued Sources
Laffort and
Dravnieks (1973)
32.05 Unreviewed Sources
No C-E Codes
Critiqued Sources
Jacobson et al.
(1955)
Jacobson et al.
(1958)
36.47 Unreviewed Sources
Schley (1934)
Heyroth (1963)
Styazhkin (1963)
Takhirov (1974)
Critiqued Sources
Melekhina (1968)
Leonardos et al.
(1969)
20.01 Unreviewed Sources
No C-E Codes
Critiqued Sources
Sadilova (1968)
110.1 No Sources Found
138.2 Unreviewed Sources
No C-E Codes
Critiqued Sources
Hellman and Small
(1974)
Hellman and Small
(1974)
Code
C4
B
-
A
A
E2
Cl
E2
El
B2
B
-
B2
-
A
A
mg/m
875
230
-
3.9-5.2
5.2
4.5
1.5-7.5
0.2
0.38
0.39
15
-
0.03
-
1.1
3
ppm
248
65
-
3.0-4.0
4
3.02
1.01-5.03
0.134
0.255
0.262
10.06
-
0.04
-
0.19
0.53
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
None Faint gasoline
ng
ns
3.7 d Ammonia
-
ng
ng
None Sharp/
ng suffocating,
d irritating
ng
ng
d
r
None
-
ng
0.19 d Sharp
0.53 r
d
r
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
Odor Thresholds
CAS # Compound Name Synonyms Formula M.W. Source
Code
mg/m
ppm
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
58899 Lindane (all isomers) CgHgCIg 290.8 No Sources Found
108316 Maleic Anhydride C4H2O3 98.06 Unreviewed Sources
2,5-Furandione No C-E Codes
Critiqued Sources
Grigor'eva (1964)
67561 Methyl Alcohol CH4O 32.04 Unreviewed Sources
Methanol Passy (1892)
Zwaardemaker
(1914)
Backman (1917)
Grijns (1919)
Jung (1936)
Jung (1936)
Gavaudan et al.
(1948)
Janicek et al. (1960)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Mullins (1955)
Scherberger et al.
(1958)
Chao-Chen-Tzi
(1959)
Pliska and Janicek
(1965)
May (1966)
May (1966)
Ubaidullaev (1966)
Leonardos et al.
(1969)
Hellman and Small
(1974)
Hellman and Small
(1974)
-
B2
D5
E2
El
E2
E2
E2
E2
El
D3
D3
B5
B
B2
B
A
A
B2
B
A
A
-
1.0-1.3
1,000
600
900-1,000
2,150
23.4-54.6
54.6-62.4
150
4,000
74
260
19,300
1,950
4.3
260,000
7,800
11,700
4.5
130
5.5
69
-
0.25-0.32
764
458
687-763
1,641
17.9-41.7
41.7-47.7
114
3,053
56
198
14,729
1,490
3.3
198,416
5,950
8,930
3.4
99
1.2
53
None Acrid, faint
-
ng
160 d Sour/sweet
d 690 r
d
r
ng
d
r
ng
ng
d
r
r
r
ng
ng
d
r
ng
r
d
r
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
K)
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds
CAS # Compound Name Synonyms
72435 Methoxychlor
74839 Methyl Bromide
Bromomethane
74873 Methyl Chloride
Chloromethane
71556 Methyl Chloroform
1,1,1 -Trichloroethane
78933 Methyl Ethyl Ketone
2-Butanone
MEK
Formula M.W. Source
C16H15C13°2 345'7 No Sources Found
CH3Br 94.94 No Sources Found
CH3CI 50.49 Unreviewed Sources
No C-E Codes
Critiqued Sources
Leonardos et al.
(1969)
C2H3C13 133.4 Unreviewed Sources
Kendall et al. (1968)
Critiqued Sources
Scherberger et al.
(1958)
May (1966)
May (1966)
C^HgO 72.1 Unreviewed Sources
Backman (1917)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
May (1966)
May (1966)
Leonardos et al.
(1969)
Mukhitov and
Azimbekov (1972)
Dravnieks (1974)
Hellman and Small
(1974)
Hellman and Small
(1974)
Hartung et al. (1971)
Code
-
B
E2
B
A
A
El
D3
D3
A
A
B
B5
A
A
A
B5
mg/m
-
>21
88
1,650
2,100
3,900
63-70
8.4
29
80
163
29
0.75
250
5.8
16
7
ppm
-
>10
16
302
385
715
21-24
2.8
9.8
27
55
9.8
0.25
85
2
5.4
2.4
Type of Threshold Type of Odor
Threshold (ppm)
None
.
r
385
r 715
r
d
r
17*
r 17
d
r
d
r
r
ng
d
d
r
ng
Threshold Characteristic
Slightly fruity
Relatively
odorless,
sweet,
chloroform
Sweet/etherish
d Sweet/etherish
r
d Sweet/sharp,
r acetone
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
N>
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
CAS # Compound Name Synonyms Formula
60344 Methyl Hydrazine CH6N2
74884 Methyl Iodide CH3I
lodomethane
108101 Methyl Isobutyl Ketone C6H12°
Hexone
MIBK
4-Methyl-2-pentanone
624839 Methyl Isocyanate C2H3NO
Isocyanic Acid-Methyl Ester
MIC
M.W. Source
46.07 Unreviewed Sources
No C-E Codes
Critiqued Sources
Jacobson et al.
(1955)
141.9 No Sources Found
100.2 Unreviewed Sources
Backman (1917)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
May (1966)
May (1966)
Stone et al.
(1967)
Steinmetz et al.
(1969)
Leonardos et al.
(1969)
Hellman and Small
(1974)
Hellman and Small
(1974)
57.05 Unreviewed Sources
Kimmerle and Eben
(1964)
Critiqued Sources
No A or B Codes
Code
-
A
El
D3
D3
A
A
B
B
B
A
A
C4
-
mg/m
-
1.9-5.7
0.6-0.8
0.7
2.8
32
64
0.97-9.7
1.21
1.9
0.4
1.1
5
-
ppm Threshold (ppm) Threshold Characteristic
1 .73 Like ammonia
-
1.0-3.0 ng
0.88 d Sweet/sharp,
0.15-2.0 r 2.1 r pleasant
0.17 d
0.68 r
7.8 d
16 r
0.24-2.4 d
0.3 d
0.46 r
0.1 d
0.27 r
None
2.1 ng
-
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
(s)
to
Odor Thresholds
CAS#
80626
1634044
101144
75092
101688
101779
Compound Name Synonyms
Methyl Methacrylate
Methyl 2-methyl-2-propenoate
Methyl Tert Butyl Ether
4,4-Methylenebis(2-Chloroaniline)
Methylene Chloride
Dichloromethane
Methylene Bisphenyl Isocyanate
Diphenylmethane 4,4-Diisocyanate
Methylene Diphenyl Diisocyanate
MDI
4,4-Methylenedianiline
para,para'-Diaminodiphenylmethane
Formula M.W. Source
C5HgO2 100.1 Unreviewed Sources
Holland (1974)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Filatova (1962)
Leonardos et al.
(1969)
Hellman and Small
(1973, 1974)
Hellman and Small
(1973, 1974)
(CH3)3COCH3 88.15 No Sources Found
C13H14C12N2 269-2 No Sour«es Found
CH2C12 84.94 Unreviewed Sources
Lehmann and
Schmidt-Kehl (1936)
Basmadshijewa et al.
(1970)
Critiqued Sources
Scherberger et al.
(1958)
May (1966)
May (1966)
Leonardos et al.
(1969)
C15H10°2N2 2^ Unreviewed Sources
Woolrich (1982)
Critiqued Sources
No A or B Codes
C13H14N2 196'3 No Sources Found
Code
D2
D3
D3
B2
B
A
A
El
E2
B
A
A
B
Cl
-
mg/m
0.057
0.62
1.9
0.2
0.85
0.2
1.4
1,100
4.1-33.2
1,530
500
790
730
4
-
ppm
0.014
0.15
0.46
0.049
0.21
0.049
0.34
317
1.2-9.6
440
144
227
210
0.39
-
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
0.049 d Plastic/sharp
ng 0.34 r
d
r
ng
r
d
r
144 d Sweet/
227 r ethereal,
ng penetrating
d
r
d
r
r
None
ng
-
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
to
Odor Thresholds
CAS tt Compound Name Synonyms
91203 Naphthalene
98953 Nitrobenzene
92933 4-Nitrobiphenyl
100027 4-Nitrophenol
Formula M.W. Source
C1QHg 128.2 Unreviewed Sources
Backman (1917)
Mitsumoto (1926)
Morimura (1934)
Robbins (1951)
Critiqued Sources
Punter (1980)
CgH<;NC>2 123.1 Unreviewed Sources
Hermanides (1909)
Zwaardemaker
(1914)
Backman (1917)
Henning (1924)
Van Anrooji (1931)
Janicek et al. (1960)
Gavaudan and
Poussel (1966)
Critiqued Sources
Allison and Katz
(1919)
Katz and Talbert
(1930)
Andreeshcheva
(1964)
Leonardos et al.
(1969)
Randebrock (1971)
C12H9NO2 199.2 No Sources Found
CgH^NOg 139.1 Unreviewed Sources
Stuiver (1958)
Critiqued Sources
No A or B Codes
Code
El
El
El
C3
A
E2
E2
El
Cl
E2
El
El
B5
A
B2
B
B5
E2
-
o
mg/m
0.05-0.055
4.0-4.4
3.37-5.34
<1.6
0.2
0.0412
0.041
0.34-7.0
0.0065
0.019
19
0.15
146
9.6
0.0182
0.024
0.002
2.3
-
ppm
0.0095-
0.0105
0.76-0.84
0.64-1.02
0.31
0.038
0.0082
0.0082
0.068-0.14
0.0013
0.0038
3.78
0.03
29
1.9
0.0036
0.0048
0.0004
0.4
-
Geometric
Mean
Air Odor
Type of Threshold
Threshold (ppm)
0.038
r
r
r
ng
d
1.9
r
d
r
d
d
ng
ng
ng
ng
ng
r
ng
None
d
-
Geometric
Mean
Air Odor
Type of Odor
Threshold Characteristic
d Tar/cresote/
mothballs
ng Almonds/shoe
polish
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
CASff
79469
684935
62759
59892
56382
82688
87865
127184
Compound Name Synonyms
2-Nitropropane
beta-Nitropropane
Dimethylnitromethane
Isonitropropane
Nitroisopropane
N-Nitroso-N-methylurea
N-Nitrosodimethyl Amine
N-Methyl-N-Nitrosomethanamine
Dimethyl Nitrosamine
DMN
DMNA
N-Nitrosomorpholine
Parathion
Ethyl Parathion
Pentachloronitrobenzene
Quintobenzene
Pentachlorophenol
Perchloroethylene
Tetrachloroethylene
Formula M.W. Source Code
CjHyNC^ 89.09 Unreviewed Sources
Treon and Dutra
(1952) Cl
Hine et al. (1978) Cl
Critiqued Sources
No A or B Codes
H2NCON(NO) 103.1 No Sources Found
CH3
C2HgN2O 74.08 Unreviewed Sources
No C-E Codes
Critiqued Sources
Prusakov et al.
(1976) B2
No Sources Found
C10H14O5PSN 291.3 No Sources Found
CgCljNC^ 295.3 No Sources Found
CgHCljO 266.3 No Sources Found
C2C1^ 165.8 Unreviewed Sources
Carpenter (1937) C4
Anonymous (1980) D3
Anonymous (1980) D3
Torkelson and Rowe
(1981) Cl
Critiqued Sources
May (1966) A
May (1966) A
Leonardos et al.
(1969) B
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
mg/m ppm Threshold (ppm) Threshold Characteristic
None Sweet, slight
297-1,050 82-288 ng
580 159 r
None
0.024-0.04 0.0079-0.013 ng
Faint
Very
weak/musty
47 d Etherish
<340 <50 ng 71 r
12 2 d
55 8 r
340 50 ng
320 47 d
480 71 r
32 5 r
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
K)
to
oo
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds
CAS # Compound Name Synonyms Formula M.W. Source
108952 Phenol C6H5OH 94-n Unreviewed Sources
Carbolic Acid; Grijns (1906)
Phenic Acid; Zwaardemaker
Phenylic Hydroxide; (1914)
Hydroxybenzene; Backman (1917)
Oxybenzene Henning (1924)
Takhirov (1974)
Punter (1975, 1979)
Makeicheva (1978)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Mukhitov (1962)
Itskovich and
Vinogradova (1962)
Pogosyan (1965)
Korneev (1965)
Makhinya (1966)
Basmadzhieva and
Argirova (1968)
Leonardos et al.
(1969)
Punter (1980)
Code
E2
E2
El
Cl
El
D1.D2
El
D3
D3
B2
B5
B2
B2
B2
B2
B
A
mg/m
2.2-6.8
4
0.13-0.26
1.2
0.022
0.8
0.027
0.046
0.22
0.022
3
0.022
0.0172
0.022
0.021
0.18
0.23
ppm
0.57-1.8
1
0.034-0.068
0.31
0.0057
0.21
0.007
0.012
0.057
0.0057
0.78
0.0057
0.0045
0.0057
0.0055
0.047
0.06
Type of Threshold
Threshold (ppm)
0.060
ng
d
r
d
ng
d
ng
d
T
ng
ng
ng
ng
ng
ng
r
d
Type of Odor
Threshold Characteristic
d Medicinal/
acid/creosote
106503 p-Phenylenediamine C6HgN2 108.2 No Sources Found
75445 Phosgene C12CO 98.92 Unreviewed Sources
Carbonyl Chloride Fieldner et al. (1921)
Schley (1934)
Schley (1934)
Patty (1963a)
Suchier (1930)
Critiqued Sources
Leonardos et al.
(1969)
Cl
E2
E2
Cl
C2
B
23
0.5
0.5-1.0
2
4
4
5.7
0.12
0.12-0.25
0.49
1
1
None
ng
d
r
ng
ng
r
Haylike
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
to
VO
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
CAS#
7803512
7723140
85449
1336363
1120714
57578
Compound Name Synonyms Formula
Phosphine PHj
Phosphorus P
Phthalic Anhydride CgHgO4
1 ,3-Isobenzofurandione
PAN
Polychlorinated Byphenyls
Aroclors
1,3-Propane Sultone
beta-Propiolactone CoHxO2
M.W. Source Code mg/nr
34 Unreviewed Sources
Valentin (1848) D5 1.4
Valentin (1850) D5 0.13
Singh et al. (1967) C2 7
Berck (1968) C2 <2
Critiqued Sources
Leonardos et al.
(1969) B 0.03
Fluck (1976) A 0.014-2.8
30.97 No Sources Found
166.1 Unreviewed Sources
No C-E Codes
Critiqued Sources
Slavgorodskiy (1968) B2 0.32
No Sources Found
No Sources Found
72.07 No Sources Found
ppm Threshold (ppm) Threshold Characteristic
1 .0 ng Garlic
1 ng
0.094 ng
5 d
<1.4 r
0.022 r
0.010-2.014 ng
Practically
odorless
None Choking
-
0.053 ng
Pungent
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds
CAS#
123386
114261
78875
75569
Compound Name Synonyms
Propionaldehyde
2-Propynal
Propoxur (Baygon)
Orthoisopropoxyphenyl-N-
methylcarbamate
Propylene Bichloride
1 ,2-Dichloropropane
Propylene Oxide
Methyloxidrane
Propene Oxide
1 ,2-Epoxypropane
Formula M.W. Source
C3H6O 58.08 Unreviewed Sources
Backman (1917)
Knuth (1973)
Bedborough and
Trout (1979)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Hartung et al. (1971)
Pliska and Janicek
(1965)
Teranishi et al.
(1974)
Hellman and Small
(1974)
Hellman and Small
(1974)
C11H15NO3 209'2 No Sources Found
CjHgC^ 113 Unreviewed Sources
No C-E Codes
Critiqued Sources
Hellman and Small
(1974)
Hellman and Small
(1974)
CjHgO 58.08 Unreviewed Sources
No C-E Codes
Critiqued Sources
Jacobson et al.
(1956)
Hellman and Small
(1974)
Hellman and Small
(1974)
Code
El
D2
E2
D3
D3
B5
B
B3
A
A
-
A
A
-
A
A
A
mg/m
0.02
0.026
0.014
0.0036
0.036
1.7
0.022
0.02
0.2
0.1
-
1.2
2.4
-
473
24
84
ppm
0.008
0.011
0.0058
0.0015
0.015
0.72
0.0093
0.008
0.08
0.04
-
0.26
0.52
-
199
10
35
Type of Threshold Type of Odor
Threshold (ppm)
0.04
r 0.08
ng
d
d
r
ng
ng
ng
r
d
0.26
0.52
d
r
45*
35
ng
d
r
Threshold Characteristic
d Pungent,
r suffocating,
unpleasant
Odorless
d Sweet/
r chloroform
d Sweet/ethereal
r
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
K)
CAS tt Compound Name Synonyms Formula M.W. Source
75558 1 ,2-Propyleinimine (2-Methyl Aziridine) CjHyN 57.1 No Sources Found
91225 Quinoline C9H?N 129.2 Unreviewed Sources
Geier (1936)
Geier (1936)
Critiqued Sources
Gundlach and
Kenway (1939)
106514 Quinone CgH4O2 108.1 Unreviewed Sources
1,4-Benzoquinone Backman (1917)
Oglesby et al. (1947)
Critiqued Sources
No A or B Codes
100425 Styrene, Monomer (c8Hs)n 104-1 Unreviewed Sources
Phenyl Ethylene Wolf et al. (1956)
Polystyrene Deadman and Prigg
Vinyl Benzene (1959)
Cinnamene Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Li-Shen (1961)
Stalker (1963)
Muehlen (1968)
Leonardos et al.
(1969)
Smith and
Hochstettler (1969)
Hellman and Small
(1973, 1974)
Hellman and Small
(1973, 1974)
Dravnieks (1974)
Geometric
Mean
Air Odor
Odor Thresholds Type of Threshold
Code mg/m3 ppm Threshold (ppm)
E2
E2
A
El
C3
-
E2
E2
D3
D3
B2
A
B
B
B
A
A
A
0.03
0.05-0.1
28
0.047-0.05
0.44
-
43-258
0.11
0.14
0.73
0.02
0.073
4.3
0.2-0.4
0.2
0.22-0.64
0.64
8
0.0057
0.009-0.189
5.3
0.0106-0.0113
0.1
-
10-61
0.026
0.033
0.17
0.0047
0.017
1
0.047-0.094
0.047
0.052-0.15
0.15
1.9
5.3
d
r
d
None
r
ng
-
0.15*
ng 0.15
d
d
r
ng
d
r
r
r
d
r
d
Geometric
Mean
Air Odor
Type of Odor
Threshold Characteristic
Strong,
ammonia-like
d Unpleasant/
peculiar
Irritating
d Sharp/sweet/
r aromatic,
unpleasant
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
oo
to
CAS#
96093
1746016
79345
7550450
Compound Name Synonyms Formula
Styrene Oxide C8H8°
1-Phenyl-l ,2-Epoxyethane
2,3,7,8-Tetrachlorodibenzo-p-dioxin
Dioxin
1 , 1 ,2,2-Tetrachloroethane C2H2C14
Acetylene Tetrachloride
sym-Tetrachlorethane
Titanium Tetrachloride TiCl4
Odor Thresholds
M.W. Source Code mg/m ppm
120.2 Unreviewed Sources
No C-E Codes - -
Critiqued Sources
Hellman and Small
(1974) A 0.3 0.061
Hellman and Small
(1974) A 2 0.4
No Sources Found
167.9 Unreviewed Sources
Lehmann and
Schmidt-Kehl (1936) El 20 2.9
Critiqued Sources
Dravnieks (1974) A 50 7.3
189.7 No Sourc es Found
Geometric
Mean
Air Odor
Type of Threshold
Threshold (ppm)
0.061
0.4
d
r
7.3
ng
d
Geometric
Mean
Air Odor
Type of Odor
Threshold Characteristic
d Sweet/pleasant
r
d Solvent
Acrid, choking
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
OO
Odor Thresholds
CAS # Compound Name Synonyms Formula M.W. Source
108883 Toluene C7Hg 92.13 Unreviewed Sources
Toluol; Backman (1917)
Methylbenzene; Backman (1918)
Phenylmethane Grijns (1919)
Schley (1934)
Schley (1934)
Deadman and Prigg
(1959)
Koster (1971)
Naus (1962)
Winneke and Kastka
(1975)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Nader (1958)
Stalker (1963)
Gusev (1965)
May (1966)
May (1966)
Leonardos et al.
(1969)
Dravnieks and
O'Donnell (1971)
Hellman and Small
(1973, 1974)
Hellman and Small
(1973, 1974)
Dravnieks (1974)
Punter (1980)
Code
El
E2
E2
E2
E2
E2
E2
Cl
E2
D3
D3
A
A
B2
A
A
B
B5
A
A
A
A
mg/m
3.5-3.6
2
170
6
16
5.5
13.7
2
46-84
3.5
18
0.08-1.9
1
1.5-3.2
140
260
8.1-17.8
45
0.6
7
60
25.4
ppm
0.93-0.96
0.53
45
1.6
4.2
1.5
3.6
0.53
12-22
0.93
4.8
0.021-0.50
0.27
0.40-0.85
37
69
2.1-4.7
12
0.16
1.9
16
6.7
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
2.8 d Sour/burnt,
t 1.6 r benzene-like
ng
ng
d
r
d
d
d
ng
d
I
ng
d
ng
d
r
r
ng
d
r
d
d
95807 2,4-Toluene Diamine C7Hj0N2 122.2 No Sources Found
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
K>
CAS#
584849
95534
8001352
120821
79005
Compound Name Synonyms Formula
2,4-Toluene Diisocyanate C9HgN2O2
Tolylene Diisocyanate
2,4-Diisocyanato-l-methylbenzene
o-Toluidine CjHpN
2-Methylbenzenamine;
1 - Amino-2-methy Ibenzene ;
2-Methylaniline;
2-AminotoIuene
Toxaphene ''lO^lO^'s
Chlorinated Camphene
1 ,2,4-Trichlorobenzene CgHgClg
1,1,2-Trichloroethane C2H3C13
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
M.W. Source Code mg/m ppm Threshold (ppm) Threshold Characteristic
174.2 Unreviewed Sources None Sharp/pungent
Zapp (1957) Cl 2.8 0.4 ng
Henschler et al.
(1962) C3 0.14-0.35 0.020-0.050 ng
Chizhikov (1963) El 0.2 0.03 ng
Critiqued Sources
Leonardos et al.
(1969) B 15 2.11 r
107.2 Unreviewed Sources None
Huijer(1917) E2 29 6.6 d
Backman (1917) El 4.0-5.4 0.91-1.23 r
Stuiver (1958) E2 0.11 0.025 d
Critiqued Sources
No A or B Codes - -
413.8 No Sources Found Mild, chlorine,
camphor
181.5 Unreviewed Sources None Aromatic
Rowe (1975) D2 22 2.96 ng
Critiqued Sources
No A or B Codes - -
133.4 No Sources Found Chloroform-
like, sweet
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
CAS $ Compound Name Synonyms Formula M.W. Source Code mg/m ppm Threshold (ppm) Threshold Characteristic
79016 Trichloroethylene C2HC13 131.4 Unreviewed Sources
1 , 1 ,2-Trichloroethylene; Lehmann and
TCE; Schmidt-Kehl (1936) El
Trichloroethene Weitbrecht (1957) Cl
Frantikova (1962) E2
Naus (1962) Cl
Torkelson and Rowe
(1981) Cl
Critiqued Sources
Scherberger et al.
(1958) B
May (1966) A
May (1966) A
Malyarova (1967) B5
to Leonardos et al.
U> (1969) B
95954 2,4,5-Trichlorophenol CgHgCljO 197.5 No Sources Found
88062 2,4,6-Trichlorophenol CgH-jCIjO 197.5 Unreviewed Sources
Backman (1917) El
Kendall et al. (1968) E2
Critiqued Sources
Punter (1980) A
121448 Triethylamine CgHjjN 101.2 Unreviewed Sources
No C-E Codes
Critiqued Sources
Tkachev (1970) B5
Hellman and Small
(1974) A
Hellman and Small
(1974) A
Laing et al. (1978) A
Romans et al. (1978) A
900
110
69
3
538
410
440
580
2.5-21
115
0.0010-0.0016
0.021
0.00016
-
0.33
<0.4
1.1
11.9
2.7
167
20
13
0.56
100
76
82
108
0.5-4.0
21
0.0001-0.0002
0.0026
0.00002
-
0.08
<0.10
0.27
2.9
0.65
82
108
ng
ng
ng
d
ng
r
d
r
ng
t
0.00002
r
r
d
<0.10
0.88
ng
d
r
r
ng
d Ether/solvent,
r chloroform
Strong
disinfectant
d Strong
disinfectant
d Fishy/ammonia
r
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
ON
CAS#
1582098
540841
108054
593602
75014
75354
1330207
Compound Name Synonyms
Trifluralin
2,2,4-Trimethylpentane
Isooctane
Vinyl Acetate
Vinyl Bromide
Vinyl Chloride
Chloroethylene
Chloroethene
Vinylidene Chloride
1 , 1 -Dichloroethy lene
Xylene (Dimethylbenzene)
See o-Xylene
See m-Xylene
See p-Xylene
Odor Thresholds
Formula M.W. Source Code mg/m ppm
C13H16N3°4F3 33^'3 No Sources Found
CgHjg 114.2 No Sources Found
C4HgO2 86.09 Unreviewed Sources
Deese and loyner
(1969) C4 <1.4 <0.40
Critiqued Sources
Gofmekler (1960) B2 1 0.28
Hellman and Small
(1973, 1974) A 0.4 0.11
Hellman and Small
(1973, 1974) A 1.4 0.4
C2H3Br 107 No Sources Found
C2H3C1 62.5 Unreviewed Sources
No C-E Codes -
Critiqued Sources
Hori et al. (1972) B 26-52 10-20
C2H2Cl2 96.94 Unreviewed Sources
Janicek et al. (1960) El 5,500 1,390
Irish (1963) Cl 2,000-4,000 504-1,009
Dalla Valle and
Dudley (1939) E2 4.3 1.08
Critiqued Sources
No A or B Codes - -
CgH10 106.2
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
0.11 d Sour/sharp
0.4 r
r
ng
d
r
None Sweet/ethereal
ng
None
ng
ng
d
Sweet
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
K)
i
U>
-J
Odor Thresholds
CAS # Compound Name Synonyms Formula M.W. Source
95476 o-Xylene C8H10 106-2 Unrcviewed Sources
1 ,2-Dimethylbenzene Backman (1917)
Backman (1918)
Stuiver (1958)
Roster (1971)
Naus (1962)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Punter (1980)
108383 m-Xylene C8H10 106-2 Unreviewed Sources
1,3-Dimethylbenzene Backman (1917)
Stuiver (1958)
Koster (1971)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Gusev (1965)
Dravnieks and
O'Donnell (1971)
Punter (1980)
106423 p-Xylene C8H10 106'2 Unreviewed Sources
1,4-Dimethylbenzene Backman (1917)
Stuiver (1958)
Koster (1971)
Knuth (1973)
Anonymous (1980)
Anonymous (1980)
Critiqued Sources
Leonardos et al.
(1969)
Punter (1980)
Code
El
E2
E2
E2
Cl
D3
D3
A
El
E2
E2
D3
D3
B2
B5
A
El
E2
E2
D2
D3
D3
B
A
mg/m
1.0-1.2
0.8
2.1
11
1
0.77
3.1
23.6
1.1-1.3
0.35
0.7-86
0.52
2.4
0.6-1.9
1.3
1.5-4.9
1.4-1.5
0.6
8
0.8
0.52
2.2
2
9.1
ppm
0.23-0.28
0.18
0.48
2.5
0.23
0.18
0.71
5.4
0.25-0.30
0.081
0.16-20
0.12
0.55
0.14-0.44
0.3
0.35-1.1
0.32-0.35
0.14
1.8
0.18
0.12
0.51
0.46
2.1
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
5.4 d
r
ng
d
d
d
d
r
d
0.73 d
r
d
d
d
r
ng
ng
d
2.1 d
r
d
d
ng
d
r
r
d
0 Antimony Compounds No Sources Found
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
OO
CAS #
0
0
0
0
0
0
Compound Name Synonyms Formula
Arsenic Compounds
(inorganic including arsine)
Arsine AsHo
Arsenic Hydride
Diphenylcyanarsine
Ethyldichloroarsine C2HcAsCl2
Beryllium Compounds
Cadmium Compounds
Chromium Compounds
Cobalt Compounds
Coke Oven Emissions
See Polycyclic Organic Matter
See Benzene
See Toluene
Odor Thresholds
0
M.W. Source Code mg/m ppni
77.95 Unreviewed Sources
Patty (1963b) Cl <3.2 <1
Critiqued Sources
No A or B Codes - -
Unreviewed Sources
Flury (1921) C4 <0.005
Critiqued Sources
No A or B Codes - -
174.9 Unreviewed Sources
Flury (1921) C4 0.17-0.85 0.024-0.12
Critiqued Sources
No A or B Codes
No Sources Found
No Sources Found
No Sources Found
No Sources Found
No Sources Found
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
None
ng
None
ng
None Fruity
ng
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
tsi
CAS # Compound Name Synonyms Formula
0 Cyanide Compounds
Methyl Isocyanide
Methylcarbyamine
Hydrogen Cyanide HCN
See Acetonitrile
Methyl Cyanide
See Acrylonitrile
Vinyl Cyanide
0 Glycol Ethers
110805 2-Ethoxyethanol C8H16°3
Ethylene Glycol Monoethyl Ether
Monoethyl Ether of Ethylene Glycol
Cellosolve
Odor Thresholds
M.W. Source Code mg/m ppm
Unreviewed Sources
Pozlomek et al.
(1971) Cl 0.0006-0.006
Critiqued Sources
Stone and Pryor
(1967) B 0.0069-0.0127
Stone and Pryor
(1967) B 0.069
27 Unreviewed Sources
Fieldner et al.
(1921) E2 1 0.091
160.2 Unreviewed Sources
No C-E Codes - -
Critiqued Sources
May (1966) A 90 24
May (1966) A 180 49
Hellman and Small
(1973, 1974) A 1.1 0.3
Hellman and Small
(1973, 1974) A 2 0.54
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
None
r
d
r
None Faint, bitter
almonds
d
2.7 d Sweet;
5.1 r musty,
rose-like
d
r
d
r
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
k
CAS #
0
0
0
0
0
0
0
Compound Name Synonyms Formula
Glycol Ethers (cont'd)
2-Ethoxyethyl Acetate C8H16°3
Ethyl Glycol Acetate
Ethylene Glycol Monoethyl Ether
Acetate
Cellosolve Acetate
Lead Compounds
Manganese Compounds
Mercury Compounds
Fine Mineral Fibers
Nickel Compounds
Nickel Carbonyl Ni(CO)4
Nickel Tetracarbonyl
Polycyclic Organic Matter
Acenaphthene *~12^10
Naphthyleneethylene
1-Aminonaphthalene CjpHgN
Odor Thresholds
•3
M.W. Source Code mg/m ppm
160.2 Rejected/Unreviewed
Sources
No C-E Codes - -
Critiqued Sources
Hellman and Small
(1973, 1974) A 0.3 0.06
Hellman and Small
(1973, 1974) A 0.7 0.13
No Sources Found
No Sources Found
No Sources Found
No Sources Found
170.7 . Unreviewed Sources
Armit(1907) E2 3.5 0.5
Kincaid et al. (1956) Cl 7-21 1.0-3.0
Critiqued Sources
No A or B Codes
154.2 Unreviewed Sources
Lillard and Powers
(1975) E2 3.1 0.5
Critiqued Sources
No A or B Codes
143.2 Unreviewed Sources
Backman (1917) El 0.014-0.29 0.024-0.5
Critiqued Sources
No A or B Codes - -
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
0.06 d Sweet/ester/
0.13 r fruity
d
r
None Sooty
ng
ng
None
d
None
r
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
ts>
CAS H Compound Name Synonyms Formula
0 Polycyclic Organic Matter (cont'd)
1-Hydroxynaphthalene Cj0HgO
1-Naphthol
alpha-Naphthol
2-Hydroxynaphthalene CjQHgO
2-Naphthol
beta-Naphthol
Indene CgHg
Indonaphthene
Indole CgNH7
1 -Benzo[b]pynole
3-Methylindole C9HgN
Skatole
Phenanthrene CJ^HJQ
M.W. Source
144.2 Unreviewed Sources
Backman (1917)
Critiqued Sources
No A or B Codes
144.2 Unreviewed Sources
Backman (1917)
Critiqued Sources
No A or B Codes
1 17.2 Unreviewed Sources
Deadman and Prigg
(1959)
Critiqued Sources
No A or B Codes
1 17.2 Unreviewed Sources
Punter (1975, 1979)
Templaar (1913)
Critiqued Sources
No A or B Codes
131.2 Unreviewed Sources
Hermanides (1909)
Zwaardemaker
(1914)
Van Anroqji (1931)
Critiqued Sources
Katz and Talbert
(1930)
178.2 Unreviewed Sources
Backman (1917)
Critiqued Sources
No A or B Codes
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
Code mg/m ppm Threshold (ppm) Threshold Characteristic
None
El 0.0030-0.0052 0.00051- r
0.00088
- - -
None Faint, phenolic
El 0.23-0.30 0.040-0.051 r
-
None
E2 0.02 0.004 d
-
None Strong/
D1,D2 0.0071 0.015 d unpleasant,
E2 0.0006 0.00013 d weak/pleasant
-
0.019 Fecal
E2 0.00035 0.000065 r
E2 0.0004 0.000075 d
E2 0.00078 0.00015 d
A 0.1 0.019 ng
None
El 0.055-0.06 0.0075-0.0082 r
-
-------
TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS FROM ALL SOURCES
to
Odor Thresholds
CAS # Compound Name Synonyms Formula M.W. Source
Code
mg/m
ppm
Geometric Geometric
Mean Mean
Air Odor Air Odor
Type of Threshold Type of Odor
Threshold (ppm) Threshold Characteristic
0 Polycyclic Organic Matter (cont'd)
110861 Pyridine C5H5N 79-* Unreviewed Sources
Azabenzene Tausch (1974)
Azine Zwaardemaker
(1914)
Sales (1958)
Geier (1936)
Geier (1936)
Van Anrooji (1931)
Hermanides (1909)
Koelega (1974)
Hangartner(1981)
Dalla Valle and
Dudley (1939)
Washburn (1926)
Washburn (1926)
Tausch (1974)
Moncrieff(1951)
Amerine et al. (1965)
Janicek et al. (1960)
Backman (1917)
Sutton (1963)
Critiqued Sources
Laffort and
Dravnieks (1973)
Allison and Katz
(1919)
Kristesashvili (1965)
Leonardos et al.
(1969)
Jones (1955c)
Katz and Talbert
(1930)
Dravnieks (1974)
Laing et al. (1978)
See Quinoline
See 2-Acetylaminofluorene
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
E2
El
El
El
Cl
B
B5
B2
B
B
A
A
A
198.5
0.04
0.42
0.095
0.09
0.078
0.16
25,391
0.08-2.9
3.7
0.00041
1.58
31,482
0.97
0.74
4.6
0.02
<3.2
0.74
32
0.21
0.067
40
0.074
6
2.4
61.4
0.012
0.13
0.03
0.028
0.024
0.049
7,849
0.025-0.90
1.14
0.00013
0.49
9,730
0.3
0.23
1. 42
0.006
<1.0
0.23
9.9
0.06
0.021
12
0.023
1.85
0.74
1 .85 d Nauseating
d 0.74 r
d
ng
r
d
d
r
d
ng
d
ng
ng
d
d
d
ng
r
ng
ng
ng
ng
r
d
ng
d
r
-------
_ TABLE 2-1 (cont'd). REPORTED ODOR THRESHOLDS EROM ALL SOURCES _
Geometric Geometric
Mean Mean
Air Odor Air Odor
Odor Thresholds Type of Threshold Type of Odor
CAS # Compound Name Synonyms Formula M.W. Source Code mg/m ppm Threshold (ppm) Threshold Characteristic
0
0
Radionuclides
Selenium Compounds
Hydrogen Selenide
No Sources Found
80.98 Unreviewed Sources None
H2Se Dudley and Miller
(1941) Cl <1.0 0.3 ng
Critiqued Sources
No A or B Codes - -
Garlic
The mean detection threshold may be greater than or equal to the recognition threshold as a result of pooling several data sets.
Ki
-------
3. REFERENCES
Agency for Toxic Substances and Disease Registry. (1988) lexicological profile for cyanide. Atlanta, GA: U.S.
Department of Health and Human Services.
Alibaev, T. S. (1970) Hygienic standards for cyclohexane and its mixture with benzene in air. Hyg. Sanit.
(USSR) 35: 22-28.
Allison, V. C.; Katz, S. H. (1919) An investigation of stenches and odors for industrial purposes. J. Ind. Eng.
Chem. 11: 336-338.
American Conference of Governmental Industrial Hygienists. (1986) TLVs: threshold limit values and biological
exposure indices for 1986-1987. Cincinnati, OH: American Conference of Governmental Industrial
Hygienists.
American Industrial Hygiene Association. (1989) Odor thresholds for chemicals with established occupational
health standards.
Amerine, M. A.; Pangborn, R. M.; Roessler, E. B. (1965) Principles of sensory evaluation of food. New York,
NY: Academic Press.
Amoore, J. E.; Hautala, E. (1983) Odor as an aid to chemical safety: odor thresholds compared with threshold
limit values and volatilities for 214 industrial chemicals in air and water dilution. J. Appl. Toxicol.
3: 272-290.
Andreeshcheva, N. G. (1964) Substantiation of the maximum permissible concentration of nitrobenzene in
atmospheric air. Hyg. Sanit. (USSR) 29: 4-9.
Anonymous. (1980) Reports of studies on the measurement of the offensive odors (from 1972-1980) (in Japan).
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