Odor Thresholds and Irritation Levels of Several Chemical

Odor Thresholds and Irritation Levels of Several Chemical

Odor Thresholds and Irritation Levels of Several Chemical Substances:
A Review
JON H. RUTH
Wausau Insurance Companies, 550 California Street, San Francisco, CA 94120.
A collation of odor threshold data ,for approximately 450 chemical substances is presented. The range of odor thresholds reported in the
literature is showlf along with any reported threshold of irritation to humans. Th~se data can assist the industrial hygienist in determining .
when an "odor"may be in excess of the Threshold Limit Value®, when an organic vapor respirator is not acceptable due to the lack of an odor
warning at the end of a cartridge life, and where odors may not indicate a hazard due to extremely low odor thresholds which may be well
below the respective TLVs.
Introduction
Although the sense of smell cannot be relied upon to evalu­
ate the hazards of chemicals used in the workplace, the
ind ustrial hygienist can use the odor threshold of a chemical
in the recognition phase as a rough estimation of airborne
concentration. The purpose of this effort is to gather
together, in one listing, the odor threshold and irritation
level data published in several less accessible formats. The
range from the lowest reported odor threshold to the highest
reported odor threshold is reported. A brief review of the
information available on our sense of smell and odors is
presented along with a short review of several methods of
defining a threshold of odor. Through an understanding of
how the odor data have been developed ,and knowing the
range of odor thresholds, the industrial hygienist can use
these odor thresholds intelligently as a tool in the recogni­
tion of potential hazards.
Methodology
The odor thresholds and irritation levels.of several hundred
chemicals were taken from the industrial hygiene literature(l-lO)
and other compilations of odor threshold data.(1l-24) The
odor thresholds were recorded as a range from the lowest to
the highest concentration reported. Whenever information
was discovered with a reported odor threshold lower or
higher than the current data base range, the appropriate
value was changed. The concentration level where irritation
begins was recorded where available. Subjective descriptions of the odors were also included where they have been
determined. Finally, the American Conference of Governmental Indust,/~ial Hygienists - Threshold Limit Value(25) was
added to th~' comput¢r data base where a TLV has been
assigned; These data w,kreentered into a personal computer
database program (Apple II+ using DB Master software)
for manipulation (conversion of ppm data into mg/ m3 ),
alphabetization and custom report generation (e.g., potential for separation ~f chemicals into groiJps with odors below
the TLV vs. those with odors above the TLV).,
In Table I, the data are presented in alphabetical order
with both the lowest and highest thresholds given in mg/ m3 •
The range of odor thresholds reported for a given chemical
should allow the industrial hygienist to interpret the odor
with a proper sense of caution. A description of the odor and
the threshold of irritation are also presented. The TLVs,
available in the computer data base, have not been included
in Table I since they are not directly used in this format for
the data.
History
In early times, Plato categorized odors as either pleasant or
unpleasant. Several centuries later, Linnaeus, a Swedish
scientist, proposed seven odoriferous qualities: I) aromatic, ,
2) fragrant, 3) musky, 4) garlicky, 5) goaty, 6) repulsive, and 7)
nauseous. A 20th Century Dutch physiologist added ethe­
real (fruity) and empyreumatic (b1.!rnt organic matter) plus
several subdivisions to the previous classifications.(26) In "
those early times, the research consisted of categorizing
various chemicals based on the description of their odor
quality. More recent research has concentrated on determin­
ation of the odor threshold, or the quantitative amount of
chemical in air which can be detected by the human sense of
smell.
Physiology of Smell
For a person to smell something, air containing odoriferous
molecules must reach a tiny cluster of specialized nerve cells
well inside the nasal cavity. These nerve cells, the olfactory
neurons, are at the top of the nose, just above the bridge,
and are positioned out of the major airstream. Each nasal
cavity has about five million ofthese receptors which are the
only nerve cells in the body which have the ability to regen­
erate. Inhaled air first passes across a series of small bones,
the turbinates, which create turbulence and cause a sm.all
amount of air to reach the odor receptors. Sniffing creates
strong eddy currents that force more air into the upper
portion of the nose and greatly increases the sense of
smell.(17,26) Together with the actual flow rate of the air in the
nose, it has been shown that air temperature and relative
humidity also affect the perception of odors.(21)
;-<,~
Copyright 1986, American Industrial Hygiene Association
A-142
Am, Ind, Hyg, Assoc, J. (47)
March, 1986
Am,
:;i
The ten million olfactory neurons can perceive some 4000
ifdifferent odors.(17) A Yale University study has shown that
4the average person can correctly name only a handful of
~~'common odors. This limitation, however, seems to be a
~result of an inability to think of the name of the substance
.\1~ rather than a failure t~~ detect the differences between the
10dors.(26) Although women are not better able to detect
~i odors than men, they are more a ware of the odor environ­
illlent and can identify more odors than men.(26) Constant
. ;;f ~xposure to odors can ind uce non-perception as the olfac­
tory neurons become fatigued. People tend to become accus­
,;' tomed to odors, even those which they initially find unpleas­
ant. Two different odors presented simultaneously can be
distinguished from one another if their characteristic odors
are sufficiently different from each other. Chemicals used to
mask odors can eventually be detected separately from the
odor these chemicals were supposed to be masking.
'1
f
c'
i'
t'
f
€~
Determination of Threshold
The method of defining and determining the threshold of
odor varies widely, giving rise to a significant range from low
to high in the odor thresholds reported. A wide variation in
threshold definition, sample presentation, panel selection,
purity of chemicals used and data interpretation have
resulted in data that seem to lack consistency. (21)
A classical definition of odor threshold is the minimum
concentration of an odorant which produces a noticeable
change in the odor of the system.(21) The threshold is often
designated as the lowest concentration perceived after no
anomalies OCCUr.(27) Common anomalies are the perception
of an odor when a blank or zero concentration sample is
presented and not perceiving an odor at a concentration
higher than that at which an odor was previously noticed.
Another definition sometimes used is the recognition odor
threshold: the minimum concentration at which the odor
quality (description of smell) of the compound can be de­
scribed. Minor differences in concentration are beyond olfac­
tory discrimination. It takes approximately a 30% to 60%
increase in the concentration to allow the subject panel to
consistently identify the higher concentration as higher.(17,21)
Samples may be presented in several fashions. Most
simply, the odor concentrations may be presented in simple
order of increasing concentration from zero to the concen­
tration level first perceived. Another protocol randomly
mixes blanks, or zero concentration samples, in with the
odor samples which are presented otherwise in simple order
of increasing concentration. These presentations in order of
increasing concentration are called serial tests.(28) Finally,
the odor concentrations may be presented in a random
fashion to minimize any sample order bias. Where odor
recognition is the definition of the threshold, a triangle test
is used most often, in which two odors are presented and
compared.(2o.28) Panel selection ranges from trained "sniffers"
to the general population. A quick sniff of the sample yields
a better perception of the odor than a slow, even inhalation.
Trained "sniffers" would understand how to sniff for the
odor and be more experienced in describing the quality of
the odor.
Acenaphthene
Acetaldehyd.e
Acetic acid
Acetic anhydride
Acetone
Acetonitrile
Acetophenone
Acetyl acetone
Acetylene
Acrolein
Acrylic acid
Acrylonitrile
Aldrin
Allyl alcohol
Allyl Alcohol (N-)
Allyl amine
Allyl chloride
Allyl disulfide
Allyl glycidyl ether
Allyl isocyanide
Allyl isothiocyanate
Allyl mercaptan
Allyl sulfide
Ammonia
Am. Ind. Hyg. Assoc. I (47)
March, 1986
Odor.Low
mg/m"
0.5048
0.0002
2.5000
0.5600
47.4666
70.0000
0.8347
0.0409
657.2000
0.0525
0.2820
8.1000
0.2536
1.9500
150.0000
14.5080
1.4100
0.0005
44.0000
0.0610
0.0325
0.0002
0.0007
0.0266
1:
OJ
.~
0­
o
U
'uj
::>
>.
.c
"0
2
2
iC,,)
e
0­
,,2
>.
Cll
E
"0
C
Cll
~
Cll
0­
"E
;S
Cll
>.
.c
Q)
c
'u
'6
Q)
:2
15
~
Cll
.c
:.::i
'iii
c
o
16
z
'Q)
Data may be interpreted in several different ways. The
odor threshold may be set at the lowest concentration per­
ceived by a single subject (absolute threshold), which, of
course, would yield the lowest concentration of an odor
threshold. Other researchers determine the threshold as that
concentration where 50% of the test subjects notice the odor
TABLE I
Odor Thresholds and Irritation Concentrations of Chemicals
Chemical Compound
~
Odor High Description
mg/m"
of Odor
0.5048
4.1400
250.0000
1.4400
1613.8600
70.0000
2.9460
0.0409
657.2000
37.5000
3.1200
78.7500
0.4027
5.0000
150.0000
14.5080
75.0000
0.0005
44.0000
5.4240
1.7052
0.0515
0.0007
39.6000
Green, sweet, fruity
Sour, vinegar-like
Sharp odor, sour acid
Minty chemical, sweet
Ether-like
Sweet, almond
Burnt, sweet
Rancid, sweet
Onion-Garlic pungency
Pungent, mustard
Green, garlic, oniony
Sweet
Sweet, repulsive
Mustard oil
Garlic-like
Pungent, irritating
Irritating
Cone. mg/m"
90.00
25.00
20.00
474.67
875.00
1.25
12.50
187.20
75.00
38.06
1144.00
17.02
17.05
454.50
6500.64
72.00
A-143
, :E
15
c
o
13
~
"8
Q)
:E
ODOR THRESHOLDS AND IRRITATION LEVELS: A REVIEW
TABLE I
Odor Thresholds and Irritation Concentrations of Chemicals
Odor Low
Chemical Compound
-I
::r
CD
3
III
CD
~
0
='
50.
iii'
"0
III
to
CD
::E
III
IJl
8,
"2. ,
~
_I
a
3
50
CD
()
Q.
CD
()
"=''"
0
-
0
50
CD
z
~
='
Q!.
0
r­
5'
iii
-<0
s:
CD
-
0..
5:
='
CD
cr
'<
III
50
a
"0
III
;:+
'<
III
='
0..
3
III
'<
cr
CD
"0
a
CD
CD
0..
()
cr
'<
c
0
0
0
"0
'<
~.
mg/m 3
Carbon tetrachloride
300.0000
from CH,
Caryophyllene
0.5350
Cellosolve
2.0350
Cellosolve 'acetate
0.3024
Cellosolve solvent
1.1040
Chloral
0.2825
Chlordane
0.0084
Chlorinated Camphene
23689
Toxaphene
Chlorine
0.0300
Chlorine Dioxide
0.3000
Ch loroacetaldehyde
3.0000
Chloroacetophe none (alpha-)
0.1020
Chlorobenzene
0.9800
Chlorobenzylidene malonitrile (ortho-)
Chlorobromomethane
2100.0000
Chloroform
250.0000
Chlorophenol
0.0189
Chloropicrin
5.4600
Chlorotoluene
0.2350
Citral
0.3738
Coumarin
0.0020
0.0012
Cresol
0.1050
Crotonaldehyde
Cumene
0.0392
500.0000
Cyanogen
2.0000
Cyanogen chloride
Cyclobutylamine
97.1750
309.2600
Cycloheptylamine
Cyclohexane
1.4350
Cyclohexanol
400.0000
Cyclohexanone
0.4800
106.0000
Cyclohexylamine
5.0667
Cyclopentadiene
0.1031
Cyclopentyl acetate
676.4000
Cyclopentylamine
153.5170
Cyclopropylamine
5.0725
OOT
0.3600
Decaborane
565.0000
Decalin
11.9510
Decanoic acid
0.0006
Decanol
1.3440
Diacetone alcohol
0.0035
Diacetyl
0.0005
Diallyl sulphide
0.7752
Dibenzofuran
Diborane
2.0000
Dibromo-3-chloropropane (1,2-)
0.0965
Dibutylamine
0.4224
0.4232
Dibutylamine (N-)
1.2144
Dichloroacetic acid
Dichloroanisole (2,6-)
0.0003
Dichlorobenzene (ortho-)
12.0000
Dichlorobenzene (para-)
90.0000
Dichloroethane
445.5000
Dichloroethyl ether
90.0000
Dichloroethylene (1,2-)
0.3358
Dichlorophenol (2,4-)
1.4007
Dicyclo pentadiene
0.0297
Diethyl disulfide
0.0195
Diethyl ethanolamine
0.0536
3.1725
Diethyl ketone
Diethyl pyrazine (2,5-)
0.0336
Diethyl selenide
0.0617
Odor High Description
mg/m"
of Odor
Irritating
Cone. mg/m 3
1500.0000 Sweet, pungent
0.5350
185.0000
270.0000 Sweet, musty
2.0240
0.2825 Sweet
0.0419
2.3689
15.0000
0.3000
3.0000
0.1500
280.0000
Bleachy, pungent
Sharp, pungent
Sharp, irritating
Sharp, irritating
Sweet, almond-like
Peppery
2100.0000 Sweet
1000.0000
6.5224 Medicinal, empyrumatic
7.7000 Sharp, penetrating
0.2350 Pungent, irritating
0.3738
0.0120 Pleasant, vanilla
22.0000 Sweet, creosote, tar
3.0000 Pungent, suffocating
6.3700 Sharp, aromatic
500.0000 Pungent
2.0000
340.8600
573.4000
1.4350 Sweet, aromatic
400.0000 Camphor-like
400.0000 Sweet, pepperminty
448.0000
5.0667
0.1031
2278.4000
153.5170
5.0725
0.3600
565.0000
112.4800
43.2820
480.0000 Sweet
0.0880
0.1491 Garlicky
1.6150
4.0000 Repulsively sweet
0.2895
1.4256
2.5392 Fishy, amine
1.2144
0.0003
300.0000
180.0000 Mothballs
810.0000 Chloroform-like
2160.0000
1975.0000 Acrid, eth.ereal
1.4007
0.0540 Sharp. sweet
0.0195
0.1948 Amine
49.3500
0.1120
0.0617 Putrid
9.00
15.00
3.00
0.05
933.33
1.52
20480.00
6801.18
2.10
23.01
32.00
1050.00
200.00
100.00
565.00
240.00
1.93
150.00
240.00 .
600.00
2.70
;:r
iii
::E
Am. Ind. Hyg. Assoc. 1. (47)
TABLE I (cont.)
Chemical Compound
Amyl acetate (N-)
Amyl acetate (sec-)
Amyl alcohol (iso-)
Amyl alcohol (N-)
Amyl alcohol (tert-)
Amyl amine (N-)
Amyl mercaptan
Amyl mercaptan Oso-)
Aniline
Anisole
Apiole
Arsine
Azelidine
Azine
Azole
Benzaldehyde
Benzene
Benzene hexachloride
Benzenethiol
Benzothiazole
Benzyl chloride
Benzyl mercaptan
Benzyl sulfide
Biphenyl
Boron trifluoride
Bromine
Bromoacetophenone
Bromochloromethane
Bromoform
Butadiene (1,3-)
Butadiene dioxide
Butane
Butenethiol (2-)
Butyl acetate (iso-)
Butyl acetate (N-)
Butyl acrylate Oso-)
Butyl alcohol (iso-)
Butyl alcohol (N-)
Butyl alcohol (secondary-)
Butyl alcohol (tertiary-)
Butyl amine (N-)
Butyl celloso/ve
Butyl cellosolve acetate
Butyl chloride (N-)
Butyl ether (N-)
Butyl formate
Butyl furan (2-)
Butyl lactate (N-)
Butyl mercaptan
Butyl sulfide
Butyl toluene (P-, tertiary-)
Butylamine
Butylene
Butylene oxide
Butylthiazole (2, iso-)
Butyraldehyde
Butyric acid
Butyric acid Oso-)
Camphor (synthetic)
Caprolactam
Capryl alcohol
Carbitol
Carbitol acetate
Carbon disulfide
Carbon tetrachloride
from CS 2
-l
=
(1)
3t\)
'iii'
~
0
::l
g.
a
"'0
t\)
~
t\)
::l
a.
3
t\)
'<
0-
ct>
"'0
a
m:
n,
'iii'
0.,
rr
'<
C
en
•
I
O.
0
"'0
~
cO'
;r
. Hyg Assoc. J (47)
March, 1986
Odor Low
mg/m"
Odor High Description
mg/m"
of Odor
00265
0.0107
25.2000
04332
0.8303
566G40
0.0001
0.0018
0.0002
0.2210
0.0570
0.8400
51.9200
31.6480
134.2600
0.0008
4.5000
0.0015
0.0012
04424
0.2350
0.0132
0.0184
0.0062
4.5000
0.3290
0.1221
16800000
5300.0000
0.3520
176000
2.8500
0.0001
0.0090
33.1333
0.0110
0.3600
0.3600
131.1500
219.0000
0.2400
0.4800
0.7194
3.3352
0.3731
70.8900
50.8000
35.0000
0.0016
0.0897
300000
3.0000
54.9600
0.2058
0.0202
0.0136
0.0010
29.1600
7.8000
28.0000
371000
00107
25.2000
72.2000
0.8303
132.0760
0.0018
0.0018
350.000d
0.2210
0.0570
2.0000
169.9200
66.2400
295.9200
0.1823
270.0000
142.8000
279.0000
2.2120
1.5500
0.2028
0.0184
0.3000
4.5000
24.5000
1.3838
1680.0000
5300.0000
2.8600
17.6000
14.6300
0.0001
90.0000
94.6666
0.0660
225.0000
150.0000
131.1500
219.0000
6.0000
288.0000
1.3080
6.3293
2.5051
834000
50.8000
35.0000
00033
0.0897
30.0000
378.0000
54.9600
2.0874
0.0202
26.5500
9.0000
29.1600
1200.0000
28.0000
1.1508
0.1872
0.0243
60.0000
6.0280
1.8936
23.1000
128.4000
'~
Fruity, banana, pear
Irritating
Cone. mg/m.l
530.00
Sweet
Pungent, amine-like
Garlic-like
Pleasant, bitter
Sweet, solventy
Solventy
Unpleasant
Sulfidy
20.01
9000.00
41.00
22.81
750
Pungent, irritating
Bleachy, penetrating
Unpleasant
2.10
0.33
Similar to chloroform
35.20
Pleasant, fruity
Fruity
Sweet, musty
Mild, non-residual
Sweet
Strong, pleasant
Camphor-like
Ammonical
Sweet, ester
Sweet, ester
Pungent
Fruity, sweet
1350.00
473.33
300.00
75.00
30.00
Stinks!
Gasoline-like
Ammonia, fishy
Gassy
Sweet, alcohol
48.00
30.00
Sweet, rancid
Sour, perspi ration
10.62
Sweet, pungent
Sweet, musty
Sweet
Disagreeable, sweet
Sweet, pungent
A-145
ODOR THRESHOLDS AND IRRITATION LEVELS: A REVIEW
TABLE I (cont.)
Chemical Compound
-t
::T
CD
3Q)
~
![
0
::J
5'
00'
"0
Q)
co
CD
::E
Q)
en
("):
0,
"0
CD'
Co
=r i
0
3
5'
CD
(")
Q.
CD
(")
g
::J
0
5 '
CD
z
Q)
=
0
::J
Q!.
r
cr
ill
~
0
~
CD
Co
n'
S'
CD
cr
'<
Q)
5'
a
"0
Q)
Q­
Q)
::J
Co
3Q)
'<
cr
CD
"0
<3
CD
(")
CD
Co
cr
'<
c
0
0
0
"0
~
ciS'
~
Q)
::;:
Diethyl sulphide
Diethyltrisulfide
Diethylamine
Diglycidyl ether
Diisobutyl carbinol
Diisobutyl ketone
Diisopropyl amine
Dimethoxy dimethyl pyrazine
Dimethyl acetamide
Dimethyl amine
Dimethyl disulfide
Dimethyl ethanolamine
Dimethyl formamide (N,N-)
Dimethyl napthalene
Dimethyl sulfide
Di methyl trisulfide
Dimethyltrithiocarbonate
Dimethylacetamide (N,N-)
Dimethylamine
Dimethylformamide (N,N-)
Dimethylhydrazine (1,1-)
Dioxane (1,4-)
Dioxane (para-)
Dioxolane (1,3-)
Dipentene
Diphenyl ether (perfume)
Diphenyl sulfide
Dipropylamine
Dipropylamine (N-)
Dipropylene glycol methyl ether
Dodecanol (1-)
Dodecyl Mercaptan (N-)
Dowtherm A
Endrin
Epichlorohydrin
Ethane
Ethanolamine
Ethoxy 3,4 dihydro 1,2 pyran (2-)
Ethoxy 3,4-dihyro 1,2 pyran
Ethyl acetate
Ethyl acrylate
Ethyl alcohol (synthetic)
Ethyl amine
Ethyl amyl ketone
Ethyl benzene
Ethyl benzoate
Ethyl bromide
Ethyl butanol (2-)
Ethyl ether
Ethyl formate
Ethyl hexanol (2-)
Ethyl hexyl acetate
Ethyl hexyl acrylate (2-)
Ethyl isothiocyanate
Ethyl lactate
Ethyl mercaptan
Ethyl methyl disulfide
Ethyl methylamine
Ethyl morpholine (N-)
Ethyl phenylacetate
Ethyl propyl amine
Ethyl selenide
Ethyl selenomercaptan
Ethyl silicate
Ethyl su Ifide
Odor Low
mg/m'
Odor High Description
of Odor
mg/m"
0.0177
0.0044
0.0600
25.0000
0.1885
0.6600
0.5200
1.2366
161.0000
0.0846
0.0001
0.0546
300.0000
0.0428
0.0025
0.0062
0.0331
163.8000
0.0378
300.0000
12.0000
0.0108
20.1600
44.5400
0.0117
0.0044
114.0000
25.0000
0.9424
1.8600
3.4000
1.2366
163.8000
0.0846
0.3465
0.1638
300.0000
0.0428
0.0508
0.0062
0.0331
163.8000
55.8000
300.0000
20.0000
612.0000
972.0000
335.3600
0.6950
0.0026
0.0826
0.4140
210.0000
0.0152
4222.8000
0.7000
0.2808
50.0000
184.5000
5.3333
3.1440
0.1048
0.0196
0.0008
0.3420
0.4860
31.2000
8.7000
3.8068
890.0000
0.2919
0.9900
0.6950
0.0358
227.1500
0.8280
6000.0000
0.0533
4222.8000
7.0000
6.3963
80.0000
1105.7700
10.6666
3.1440
3.1440
665.0000
32.0000
9690.000
396.0000
31.2000
870.0000
3.8068
890.0000
3.2109
3.0000
0.3990
0.5132
0.5497
6.0520
67.6200
3.2 x 10-5
0.0487
21.6900
0.3680
4.3615
60.5200
0.0003
8.0 x 10- 6
722.5000
0.0009
0.7342
1.4763
1.3554
6.0520
67.6200
0.0920
0.0487
79.5300
1.1500
4.3615
181.5600
0.003
0.0054
722.5000
0.0103
Irritating
Cone. mg/m"
Foul, garlickly
Fishy, ammonical
150.00
50.00
Sweet, alcohol
Sweet, ester
Fishy, amine
150.00
100.00
174.60
Amine
Decayed cabbage
Amine, burnt, oily
Fishy, ammonical
Fishy, pungent
Ammonical, amine-like
Ether-like
Sweet, musty
Lemon-like
Pleasant, geraniums
Burnt, rubbery
Ammonical, amine
Ammonical, amine
Ether-like
450.00
Aromatic, disagreeable
Chloroform-like
Ammonia
Sweet, fruity
Sweet, fru ity
Fruity, pleasant
Earthy, acrid, plastic
Sweet, alcoholic
Sharp, ammonical
Mild, fruity
Aromatic
Ether-like
Musty, sweet
Sweet, ether-like
Fruity
Musty
Sweet
Sharp, musty
Mustard, unpleasant
792.00
720.00
21.00
325.00
13.33
350.00
16.00
9500.00
180.00
260.00
870.00
28925.00
300.00
990.00
65.15
Garlic
Ammonia
Foul
Alcohol-like, sharp
184.00
5950.00
Am. 1M Hyg. Assoc. J (47)
TABLE I (cont.)
Odor Low
Chemical Compound
9'
a
-c
Q)
;::\.
'<
Q)
::J
c..
3
Q)
'<
g,
-c
a
CD
~
c..
0"
'<
c
0
0
0
-c
~
cO'
Ethyl valerate
Ethyl vinyl ketone
Ethylene
Ethylene diamine
Ethylene dibromide
Ethylene dichloride
Ethylene glycol
Ethylene glycol dinitrate
Ethylene oxide
Ethylenediamine
Ethyleneimine
Ethylidene norborene
Fluorine
Formaldehyde
Formamide
Formic acid
Furfural
Furfuryl alcohol
Glycol diacetate
Heptachlor
Heptanal
Heptane
Heptyl alcohol (N-)
Heptyl isobutyrate
Heptyl propionate
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexadiene
Hexane (N-)
Hexanol (1-)
Hexyl acetate (secondary-)
Hexyl isobutyrate
Hexyl propionate
Hexylene glycol
Hydrazine
Hydrochloric acid
Hydrofluoric acid
Hydrogen bromide
Hydrogen cyanide
Hydrogen peroxide
Hydrogen selenide
Hydrogen sulfide
Iodine
Iodoform
Ion one
Isoamyl alcohol
Isobutyl2-methoxypyrazine
Isobutyl 3-methoxypyrazine
Isobutyl 3-methyl pyrazine
Isobutyl butyrate
Isobutyl mercaptan
Isobutyl pyrazine (2-)
Isodecanol
Isopentanoic acid
Isophorone
Isopropyl acetate
Isopropyl alcohol
Isopropyl amine
Isopropyl ether
Isopropyl glycidylether
Kerosene
Ketene
Lauraldehyde
Linalyl acetate
Malathion
Maleic anhydride
mg/m 3
Odor High Description
mg/m 3 of Odor
0.0266
0.0004
299.0000
2.5000
76.8000
24.0000
62.5000
0.0266
0.0069
4600.0000
28.0000
76.8000
440.0000
62.5000
520.0000
25.0000
4.0000
0.0700
6.0000
1.4700
150.0000
0.0450
0.0240
32.0000
0.5552
0.3060
0.0140
200.0000
98.3250
0.0989
0.0281
12.0000
1.5000
1.6750
1400.0000
28.0000
4.0000
0.3650
6.0000
73.5000
150.0000
37.8000
20.0000
32.0000
1.8626
0.3060
0.0932
1280.0000
98.3250
0.0989
0.0281
12.0000
3.3000
127.3000
0.0417
0.0120
0.0422
0.0514
250.0000
3.0000
7.0000
0.0333
6.6667
0.9000
21.6840
600.0000
0.0422
0.0514
250.0000
4.0000
49.0000
0.1333
6.6667
5.0000
Olefinic
Ammonical, musty
Mild, sweet
Sweet
Sweet
Irritating
Cone. mg/m 3
250.00
0.18
Sweet, olefinic
Musty, ammonical
Ammonical
Sweet, ~romatic
Pungent, hay
Pungent, penetrating
Almonds
500.00
200.00
30.00
50.00
1.50
27.00
48.00
Fruity, acid
Gasoline-like
1800.00
0.0016
0.0007
9.0000
0.0062
4.63 x 10- 7
36.0000
13.5800
1.3 x 10-5
0.2146
12.3690
0.0020
2.2080
0.1292
0.0209
1.0000
0.1900
7.8400
0.5040
0.0714
1440.0000
0.5517
0.0151
50.5260
13.5000
1.8400
Sweet, alcohol
Unpleasant
250.00
Ammonical, fishy
Irritating, pungent
Strong, irritating
Sharp, irritating
Bitter almond
Slightly sharp
12.0000 Decayed horseradish
0.0140 Rotten eggs
9.0000
0.0833
573.0500
126.0000
13.5800
0.2146
17.6700
0.0020
2.2080
0.2713
0.1084
50.0000
1520,0000
490.0000
480.0000
1260.0000
1440.0000
0.5517
600.00
Musty, alc()hol
Goaty
Sharp, objectionable
Fruity
Pleasant
Pungent, ammonia
Sweet, sharp, ether
49.00
4.17
10.00
150.00
6.00
14.00
2.00
360.00
50.00
380.00
490.00
24.00
1260.00
Sharp
122.60
41.40
0.0151
50.5260
13.5000
1.9600 Acrid
5.48
~
March. 1986
A-147
, il'!I1I
i
ODOR THRESHOLDS AND IRRITATION LEVELS: A REVIEW
TABLE I (cont.)
Chemical Compound
II
Mercaptobenzothiazole
Mercaptoethanol
Mesityl Oxide
Methyl 2, cyanoacrylate
Methyl acetate
Methyl acetylene-propadiene
MAPP gas
Methyl acrylate
Methyl acrylonitrile (alpha-)
Methyl alcohol
Methyl amine
Methyl amyl acetate
Methyl amyl alcohol
Methyl anthranilate
Methyl benzyl alcohol
Methyl bromide
Methyl butanol (2-)
Methyl butenoic acid (2-)
Methyl butyl acetate
Methyl cellosolve
Methyl cellosolve acetate
Methyl chloride
Methyl chloroform
Methyl cyclohexane
Methyl cyclohexanol
Methyl disulfide
Methyl ethanolamine
Methyl ethyl ketone
Methyl ethyl pyridine
Methyl formate
Methyl furan (2-)
Methyl glycol
Methyl heptanoate
Methyl hexyl ketone
Methyl hydrazine
Methyl iodide
Methyl isoamyl alcohol
Methyl isoamyl ketone
. Methyl isobutyl'carbinol
Methyl isobutyl ketone
Methyl isocyanate
Methyl isopropenyl ketone
Methyl mercaptan
Methyl methacrylate
Methyl n-amyl carbinol
Methyl n-amyl ketone
Methyl n-propyl ketone
Methyl naphthalene (2-)
Methyl paratRion
Methyl pentaldehyde (2-)
Methyl pentane (2-)
Methyl propanol (2-)
Methyl propene (2-)
Methyl pyrazine (2-)
Methyl salicylate
Methyl styrene (alpha-)
Methyl thiocyanate
Methyl vinyl ketone
Methylamine
Methylene chloride
Methylene chlorobromide
Methylene glycol
Mineral spirits
Monochlorobenzene
Morpholine
I"
-l
=r
CD
3
*
:::!.
~
0
::>
9'
00'
"0
til
to
CD
::;;;
til
en,
n'
0,
~"
0­
~
0
3
9"
CD
n
Q.
CD
g
0
::>
0--.,
9'
CD
Z
!a
0'
::>
~
r
6'
03
-<0
--.,
:5:::
CD
0-
5:
::>
CD
cr
'<
til
9'
~
"0
til
~
til
::>
0-
3
til
'<
cr
CD
"0
a
CD
n
CD
0-
cr
'<
c
0
()
0
"0
'<
Odor Low
mg/m 3
12.0208
0.3828
0.0680
4.0000
610.0000
180.0000
70.0000
6.0000
13.1150
0.0252
0.4123
1.3761
0.0581
7235.5000
80.0000
0.0450
0.0528
0.0266
0.2880
1.6320
21.0000
542.8570
2000.0000
2350.0000
0.0012
3.0700
0.7375
0.0297
500.0000
90.4500
186.6000
0.0236
1299.5200
1.7500
Irritating
Cone. mg/m 3
Odor High Description
mg/m 3 of Odor
12.0208
2.0416
100.0000 Sweet
12.0000
915.0000 Fragrant, fruity
180.0000 Foul, objectionable
70.0000
42.0000
26840.0000
12.0000
2.3560
2.1684
0.0581
5235.5000
4000.0000
0.8280
0.0528
0.0266
288.0000
240.0000
21.0000
3800.0000
2000.0000
2350.0000
0.0039
10.4380
147.5000
94.0500
6875.0000
90.4500
279.9000
0.0236
1299.5200
5.2500
100.00
12.00
30496.90
Sharp, sweet, fruity
262.50
6.00
22875.00
24.00
Sweet
Sweet, ester
Sweet, alcohol
Sweetish
Sour, sharp
Body odor
Mild, non-residual
Sweet, ester
Sweet, ethereal
Chloroform-like
Faint, benzene-like
Weak, coconut oil
368.00
1050.00
5428.57
2350.00
Musty, ammonical
Sweet, acetone-like
Sour, pungent
Pleasant
590.00
8750.00
21500.00
0.2919
0.0576
2.0800
0.4100
1.0222
4.0 x 10'5
0.2050
0.0989
0.0940
28.0000
0.0581
0.1328
0.3681
0.2886
0.0027
45.8000
231.0000
0.6220
0.2496
0.7475
0.5720
0.0252
540.0000
2120.0000
76.2000
157.5000
0.9800
0.0350
0.8340 Pungent
0.3360
200.0000 Sweat, mild odor
192.7000 Sweet, sharp
1.0222
0.0820
1.3940
0.3378
0.0940
45.5000
0.2905
0.1328
0.5562
0.2886
0.1303
45.8000
231.0000
0.8708
960.0000
0.7475
0.5720
12.0000
2160.0000
2120.0000
76.2000
787.5000
0.9800
0.4900
100.00
410.00
5.00
Sulfidy
Arid, fruity, sulfidy
Sweet, alcohol
697.00
Sweet, rancid
Gassy
960.00
480.19
Sweet, aromatic
Sweet, unpleasant
30.00
8280.00
Fishy, pungent
Sweet
Chlorinated, mothball
Fishy, amine
:::!.
to
;or
A-148
Am. Ind. Hyg. Assoc. J. (47)
3i
~
TABLE I (cont.)
.E
C)
.~
Chemical Compound
Musk oil
Mustard gas
Myrcene
Naphthalene
Nickel carbonyl
Nitric acid
Nitric oxide
Nitrobenzene
Nitroethane
Nitrogen dioxide
Nitromethane
Nitropropane (1-)
Nitropropane (2-)
Nonane
Nonanol (2-)
Octadiene (1,3-)
Octane
Octyl alcohol
Oxygen difluoride
Ozone
Parathion
Pentaborane
Pentachlorophenol
Pentane
Pentanedione (2,4-)
Pentanol (n-)
Perchloroethylene
Perchloromethyl mercaptan
Perchloryl fluoride
Phenol
Phenyl ether
Phenyl ethyl alcohol (beta-)
Phenyl sulfide
Phenylacetaldehyde
Phosgene
Phosphine
Phthalic Anhydride
Picoline (2-)
Picric aciel
Propane
Propionaldehyde
Propionic acid
Propyl acetate (n-)
Propyl alcohol
Propyl alcohol (n-)
Propyl mercaptan
Propyl nitrate (n-)
Propyl sulfide
Propylene
Propylene diamine
Propylene dichloride
Propylene glycol dinitrate
Propylene glycol isobutyl ether
Propylene glycol methylether
Propylene oxide
Pyridine
Pyrrolidine
Quinone
Rotenone
Safrole
Silicon tetrafluoride
Skatole
Stoddard solvent
Styrene (inhibited)
Styrene (uninhibited)
Styrene oxide
. Ind. Hyg. Assoc. I (47)
March, 1986
Odor Low
mg/m 3
Odor High Description
mg/m'J
of Odor
3.8 x 10'6
0.0150
0.0723
1.5000
0.2100
0.7500
0.3600
0.0235
620.0000
2.0000
250.0000
ro80.0000
17.5000
3412.5000
0.0005
54.0000
725.0000
0.6916
0.2000
0.0010
0.4760
2.5000
0.0487
0.0150
0.0723
125.0000
21.0000
2.5000
1.2000
9.5000
620.0000
10.0000
250.0000
1080.0000
1029.0000
3412.5000
20.6150
90.0000
1208.3300
0.6916
1.0000
1.0200
0.4760
2.5000
6.6000
0.0409
0.7560
31.3560
0.0075
46.6666
0.1786
0.0070
35.0000
0.0026
0.0010
2.0000
0.0280
0.0532
0.0005
1800.0000
0.0225
0.0840
0.2100
75.0000
0.0750
0.0002
210.0000
0.0531
39.5600
0.0424
1.1667
1.2000
60.5000
360.0000
24.7500
0.0090
58.0000
0.4000
5.7960
1.4586
4.2500
4.0 x 10'7
5.2500
0.4300
0.2021
0.3093
3000.0000
0.0982
1.1160
469.0000
0.0075
46.6666
22.4200
0.7000
35.0000
0.0358
0.0196
4.0000
3.6000
0.1748
0.0005
36000.0000
0.4029
60.0000
105.0000
500.0000
150.0000
0.0746
210.0000
0.0531
116.2720
0.2030
606.6660
1.5600
60.5000
360.0000
500.0000
15.0000
187.3400
0.4000
5.7960
1.4586
4.2500
0.2680
157.5000
860.0000
860.0000
1.9640
c..
Irritating
Cone. mg/m 3
0
()
u:i
:::>
>.
.0
"t:l
Mothball, tar-like
Musty
75.00
•
~
Q)
.......
,e
]~
155:00
c..
Q)
.0
Shoe polish, pungent
Mild, fruity
Sweetish, acrid
Mild, fruity
Mild, fruity
>.
230.00
310.00
20.00
500.00
360.00
co
E
c
"t:l
co
>.
t
co
c..
"E
;S
co
>.
Gasoline-like
.0
1450.00
Q)
c
'0
Foul
Pleasant, clover-like
Garlic-like
Strong, pungent
Pungent when hot
Gasoline-like
Sour, rancid
Sweet, alcohol
Chlorinated solvent
'5
Q)
-
::2:
2.00
0
i::"
~
10.90
.0
:.:J
ro
c
0
10
z
1340.00
-
Q)
:E
Sweet
Medicinal, sweet
Disag reeable
0
c
182.40
21.00
0
1:5
~
(5
u
Q)
:E
Musty hay, green corn
Oniony, mustard, fish
8.00
10.67
30.00
E
0
.t::
"t:l
Q)
'0
Sweet
0
t.'l
Ul
1Il
3:
Ql
c
1Il
c
Sweet, ester
Sour
Sweet, ester
u:
;5
13750.00
c
Sweet, alcohol
c
Ether-like
Ii:
.;::
a:
it
E
a:
2801.40
Aromatic
Sharp, amine
Sweet
Sweet, alcoholic
Burnt, sickening
Acrid
.J:
I­
121.00
3600.00
1125.00
90.00
2.00
42.50
Perfume
Kerosene-like
Solventy, rubbery
Solventy, rubbery
Sweet
2100.00
4300.00
430.00
A-149
ODOR THRESHOLDS AND IRRITATION LEVELS: A REJIIEW
3
.!!1
.....
.c
TABLE I (cont.)
Chemical Compound
Sulfur dichloride
Sulfur dioxide
Sulfur monochloride
Sulfuric acid
Tetrachloroethane (1,1,2,2-)
Tetrachloroe.thyelene
TetraethylorthoSilicate
Tetrahydrofuran
Tetra/in
Tetramethylenediamine
Thiophene
Thiophenol mercaptan
Toluene
petroleum
Toluene
from coke
Toluene 2,4 diisocyanate
TO!
Toxaphene
Trichloro fluoromethane
Freon 11
Trichloro trifluoroethane
Freon 113
Trichlorobenzene (1,2,4-)
Trichloroethylene
TCE
Trichloropropane (1,2,3-)
Tricycloketone
Triethyl amine
Trimethyl amine
Trimethyl phosphite
Trimethylenediamine
Trinitro tert-butylxylene
musk oil
Turpentine
Valerie acid
Vanillin
Vinyl acetate
Vinyl amyl ketone
Vinyl butyl ketone
Vinyl propyl ketone
Vinyl pyridine
Vinyl toluene
Vinylidene chloride
VM&P naphtha
Xylene
Xylidene
Odor low
mg/m 3
0.0042
1.1750
Odor High Description
mg/m 3
of Odor
1.0000
21.0000
31.3560
30.6360
7.3750
97.2000
79.2000
0.0026
0.0012
8.0250
0.0042 Sulfidy
12.5000 Yech!
Nauseating
1.0000
35.0000 Sickly sweet
469.0000 Chlorinated solvent
61.2720 Sweet, alcohol
177.0000 Ether-like
97.2000
79.2000
0.0026 Aromatic
382.5000
150.0000 Rubbery, mothballs
17.5500
262.5000 Floral, pungent
od
e>
by- .~
0­
ca 0
()
Sl u:j
pr ::>
>.
ml .0
'C
tw 2
()
th 2
er e
0­
Ql
res' .0
th >.
('(J
E
su 'C
Irritating
Conc. mg/m~
5.00
12.00
1.10
1302.00
710.20
c::
co
~
co
750.00
0­
'E
750.00
;5
4.00
.0
Ql
co
3.2000
17.1200 Sweet, fruity, acrid
>.
c::
'(3
2.3660
28.0000
2.3660
1170.4000 Sweet
'6
342.0000
1026.0000 Sweet
'0
i::'
Ql
~
~
24.0000
1.1340
24.0000
2160.0000 Solventy
.0
40.00
864.00
:.:J
m
c::
o
Strong, acrid
1.8660
0.3600
0.0008
0.0005
3757.2000
3.8 x 10'6
15
300.00
870.8000
1.1200 Fishy, amine
0.0008 Fishy, pungent
0.0005 Pyridine-like
11968.5000
0.0487
'1.2
Re~
200.00
c::
o
2.
560.0000
0.0026
2.0 x 10'7
0.3600
0.5150
0.0321
0.0201
1.1670
240.0000
2000.0000
3.8700
0.3480
0.0240
1120.0000
0.0026
1.6500
0.5150
0.0321
0.0201
1.9450
240.0000
4000.0000
3.8700
174.0000
0.0240
Perfume
Sour, sharp
3.
The influence of chemical contaminants may explain
some of the variation in thresholds observed.(21) Note the
differences in odor thresholds in Table I o(toluene manufac­
tured from two different ra w materials, or carbon tetrachlo­
ride from different sources, or inhibited vs. uninhibited sty­
rene. There has been a tendency for lower thresholds to be
identified in the more recent research, which has been attrib­
A·150
Ql
.g
'C
Ql
'0
Nauseating
Disagreeable
Sweet, chloroformish
4. : 8
.' Ul
.co
.:;:
5. ! Ql
C
240.00
~
435.00
;S
6.. §
Ul
ro
~
71
or recognize an9 describe the odor. Finally, some researchers
look for a 100% panel resportse. This latter method would
generate higher concentration levels as the defined thresh­
old. One stutlY, which reported both the absolute thresh­
old and the 100% recognition threshold, showed the 100%
recognitionthresho~d to be approximately two to ten times
higher than the absolute threshold.(24)
~
"8
£
E
560.00
Sweet
Weak, amine-like
:5
1. 15
uted to greater purity of samples and better techniques
sample presentation,
0
\
I­
8.
Discussion
It must be remembered that the data listed in Table I an~'
essentially for the single chemical constituent with no othe~
chemicals present in the air. Mixtures of different chemical~'
have received very little study.(28) The question is whetheQ
two chemicals at concentrations below their odor thresholds
(RA and R B ) can add up to constitute one combined "odor"
(RAB) which is perceived, or whether the olfactory receptor~
react very specifically to each chemical so that no odor i{
perceived(17) (Figure I - Independence). There have been
several studies where two mixed chemicals, each at 50% of its
Am. Ind. Hyg Assoc. J. (47)'
~
<.U
.c
9.
10.
Am.
odor threshold, have produced an odor which was perceived
'by test subjects(17) (Figure I - Addition). While mixed chemi­
cals may betotally independent of one another or produce
simple additive effects, it is also possible that the mixture
produces an enhanced or a suppressed reaction from what
might be predicted. An enhanced reaction would result from
two mixed chemicals, each at less than 50% of its odor
threshold, which produce a perceived odor (Figure I - Syn­
ergism). A suppressed reaction, or counteraction, would
result when two mixed chemicals, each at 100% of its odor
threshold, fail to produce a perceptible oeor among test
subjects (Figure I - Counteraction).
Hygiene and Toxicology, Vol. IIC - Toxicology, 3rd rev. ed.
New York: John Wiley & Sons, 1982.
11. Hille, V.E.: Bestehen BeZiehungen Zwishen den Geruchs­
schwellenwerten undden Immissionsgrenzwerten Chemis­
cherSubstanzen? Staub Reinhalt. Luft 37(5):199-201. (1977).
12. Braker, W., A.L. Mossman and D. Siegel: Effects of Expo­
sure to Toxic Gases.- First Aid and Medical Treatment, 2nd
ed. Lyndhurst, N.J.: Matheson, 1977. pp. 7-151.
13. Manufacturing Chemists Association: Chemiclli Safety Data
Sheets. Washington" DC.
14.
Summer, W.: Odour Pollution of Air - Causes and Control.
London: Leonard Hill, 1971. pp. 22-24, 28, 43, 159.
15. National Research Council, Committee on Odors from Sta­
tionary and Mobile Sources: Odors from Stationary and
Independence,
Mobile Sources. Washington, D.C.: National Academy of
RAB = RA or RB
Sciences, 1979. pp. 24-27, .182-183.
Addition
16. American Society for Testing and Materials, Committee
RAE = RA + RB
E-18 on Sensory Evaluation of Materials and Products:
Compilation of Odor and Taste Threshold Values Data.
Synergism
Edited by FA Fazzalari. Philadelphia: ASTM.
RAB >RA + RB
17. May, J.: Odor Thresholds of Solvents for Assessment of
Counteraction
SOlvent Odors in the Air (UDC 614.718:66.062-911.
RAE < RA or RB
3:613.155.3:612.867). Staub Reinhalt. Luft 26(9):34-38 (1966).
18. Cheremisinoff, P.N. and R.A. Young, eds.: Industrial Odor
where RAB = odor threshold of mixture of chemical A and
Technology Assessment. Table 8-11. Ann Arbor, Mich.:
chemical B,
Ann Arbor Science Publishers, 1975.
RA = odor threshold of pure chemical A, and
19. Katz, S.H. and E.J. Talbert: Intensities of Odors and Irritat­
RB = odor threshold of pure chemical B.
ing Effects of Warning Agents for Inflammable and Poison­
Figure 1 - Mixed Chemicals Odor RelationshipsYSJ
ous Gases. Bureau of Mines Technical Paper 480.
Washington, D.C.: U.S. Government Printing Office, 1930.
References
20. Matsushitia, H., J. Arito, Y. Suzuki and R. Sod~: Determina­
1. American Conference of Governmental Industrial Hygien­
tion of Threshold Values for Olfactory Percep'~ion of Prim­ ists,Committee on Industrial Hygiene: Industrial Ventila­
ary Odour Substances. Ind. Health 5:221-237 (1967).
tion - A Manual of Recommended Practice, 17th ed. Lans­ (National Institute of Industrial Health, Kawasaki, Japan).
ing, Mich.: ACGIH, 1982. pp. 13-20.
21. Arthur D. Little, Inc.: Research on Chemical Odors, Part I ­
2. Billings, C.E. and L.C. Jonas: Odor Thresholds in Air as
Odor Thresholds for 53 Commercial Chemicals. Washing­ Compared to Threshold Limit Values. Am. Ind. Hyg. Assoc.
ton, D.C.: Manufacturing Chemists Association, 1965. pp.
E
J. 42:479-480 (1981).
1-26.
.g
3. American Industrial Hygiene Association: Hygienic Guide
22. Trayer, D.M.: Odor Thresholds for Air Contaminants. Safety
',r~
Series, Vol. I. Akron, Ohio: AIHA.
"0.
Newsletter - Public Utilities Section June 1976. Chicago,
8
III.: National Safety Council, 1976. p.2.
4. American Industrial Hygiene Association: Hygienic Guide
Series, Vol. II. Akron, Ohio: AIHA.
23. Occupational Health Resource Center, Oregon Lung Asso­ Q)
5. National Institute for Occupational Safety and Health:
ciation: Warning Properties of Industrial Chemicals.
c
ro
Portland, Oreg.
NIOSH/OSHA Occupational Health Guidelines for Chemi­
a
cal Hazards (DHHS/NIO$H Pub, No. 81-123). Washington,
rn
24. Hellman, T.M. and F.H. Small: Characterization of the Odor
£
D.C.: Government Printing Office, 1981.
Properties of 101 Petrochemicals Using Sensory Methods.
c:
o
6. Alliance of American Insurers: Technical Guide No.6 ­
J. Air Poll. Control Assoc. 24:979-982 (1974).
ro
Handbook of Organic Industrial Solvents, 5th ed. Chicago,
.;::
25. American Conference of Governmental Industrial Hygie­
III.: AAI, 1980. pp. 55-107.
nists: Threshold Limit Values® for Chemical Substances
E
and Physical Agents in the Work Environment with Intended
7. Alliance of American Insurers: Technical Guide No. 7 ­
G.l
Changes for 1984-85. Cincinnati, Ohio: ACGIH. 19'84. pp.
.c:
Handbook of Hazardous Materials, 2nd ed. Schaumburg,
r­
9-33.
III.: AAI, 1983. pp. 70-210.
8. Clayton, G.D. and F.E. Clayton, eds.: Patty's Industrial
26. Brody, J.E.: What the Nose Knows. This World July 24,
1983. pp. 13-14.
Hygiene and Toxicology•. Vo. IIA - Toxicology, 3rd rev. ed.
New York: John Wiley and Sons, 1981.
27. Wilby, F.V.: Variation in Recognition Odor Threshold of a
Panel. J. Air Poll. Control Assoc. 19:96-100 (1969).
9. Clayton, G.D. and F.E. Clayton, eds.: Patty's Industrial
Hygiene and Toxicology, Vol. liB - Toxicology. 3rd rev. ed.
28. Rosen, A.A., J.B. Peter and F.M. Middleton: Odor Thre­
New York: John Wiley & Sons, 1981.
sholds of Mixed Organic Chemicals. Journal WPCF.
34(1 ):7-14 (1962).
10. Clayton, G.D. and F.E. Clayton, eds.: Patty's Industrial
~
*
Am. Ind. Hyg Assoc. J. (47)
March, 1986
A·l5l