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Following are odour characteristics and odour thresholds for chemicals found in SIPCOT air in September 2004.
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Acetaldehyde |
Pungent, suffocating odor that is slightly fruity when diluted.
Recognition in air= 2.1×10-1 ppm (chemically pure) Odor low: 0.0002 mg/cu m; Odor high: 4.14 mg/cu m A wide range of values has been reported: 0.0028 to 1000 ppm. An acceptable, critiqued value is 0.067 ppm (detection).(33) Another source reports the geometric value of all published values as 0.05 ppm.(9,34) |
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Methanol |
ALCOHOLIC ODOR; PUNGENT ODOR WHEN CRUDE. Has a mild, characteristic alcohol odour, when pure. (1,31) Crude methanol may have a repulsive, pungent odour.
METHYL ALCOHOL DOES NOT HAVE SUITABLE WARNING ODOR PROPERTIES EXCEPT @ HIGH CONCN. A LEVEL OF 2,000 PPM IS BARELYDETECTABLE BY ODOR. Low threshold= 13.1150 mg/cu m; High threshold= 26840 mg/cu m; Irritating conc.= 22875mg/cu m. Reported values vary widely; 4.2-5960 ppm (geometric mean: 160 ppm) (detection); 53-8940 ppm (geometric mean: 690 ppm) (recognition) (33) |
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Toluene |
SWEET, PUNGENT, BENZENE-LIKE ODOR
2.14 ppm (8 mg/cu m). Odor recognition level is reported as 1.03 to 140 ug/cu m. Odor in air= 1.30×10 11 mol/cu cm There is a wide variation in values: 0.16 – 37 ppm (detection); 1.9 – 69 ppm (recognition).(18) |
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1,1-Dichloroethane |
CHLOROFORM-LIKE ODOR ; AROMATIC ETHEREAL ODOR
Threshold conc.: 120 ppm (no specific isomer); 200 ppm (no specific isomer). 445.5 mg/cu m (odor low) 810 mg/cu m (odor high). |
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Nitrobenzene |
ODOR OF VOLATILE OIL ALMOND; Nitrobenzene has a pungent, shoe-polish smell. Odour resembling that of bitter almonds or “shoe polish.”
Odor detection in air: 1.46×10-2 mg/l vapor/, purity not specified. Odor recognition in air: 4.70×10-3 ppm, chemically pure. Odor detection in air: 1.90 ppm, chemically pure. Nitrobenzene odor low, 0.0235 mg/cu m; odor high, 9.50 mg/cu m. Odour thresholds of 0.092 mg/m3 (0.018 ppm) (Amoore & Hautala, 1983) and 0.03 mg/m3 (0.005 ppm) (Manufacturing Chemists Association, 1968). The odour threshold in water has been reported as 0.11 mg/litre (Amoore & Hautala, 1983) and 0.03 mg/litre (US EPA, 1980). |
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Carbon Tetrachloride |
SWEETISH, AROMATIC, MODERATELY STRONG ETHEREAL; SOMEWHATRESEMBLING THAT OF CHLOROFORM
Odor recognition in air: 2.14X10 ppm (chemically pure) In water: reduction of amenities: odor threshold 50 mg/l A wide range of values have been reported; 1.6 to 706 ppm. The range of acceptable values is 140 to 584 ppm. Geometric mean air odour threshold: 252 ppm (detection); 250 ppm (recognition).(49) |
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Carbon Disulphide |
PUREST DISTILLATES HAVE SWEET, PLEASING, & ETHEREAL ODOR USUAL COMMERCIAL AND REAGENT GRADES ARE FOUL SMELLING ; When pure,carbon disulfide has sweetish aromatic odor similar to that of chloroform.
0.1 to 0.2 PPM Detection, odor, in air; purity not specified: 2.60×10-3 mg/l (gas).Recognition, odor, in air; purity not specified: 2.10×10-1 ppm. Odor Low: 0.0243 mg/m Odor High: 23.1 mg/m Reported values vary widely and are not reliable; 0.022 ppm (detection); 0.21 ppm (recognition); 0.016 to 0.42 ppm (methods not specified).(28) |
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Epichlorohydrin |
ODOR IS GENERALLY PERCEIVED AS A SLIGHTLY IRRITATINGCHLOROFORM-LIKE ODOR. ; Pungent, garlic; sweet; chloroform-like.
SENSORY PERCEPTION STUDIES INDICATE THAT MEAN THRESHOLD FORODOR RECOGNITION IS APPROX 10 PPM @ 25 PPM IT IS RECOGNIZED BYMAJORITY OF PERSONS. Human Odor Perception: non perception 0.2 mg/cu m; perception 0.3 mg/cu m Threshold 38-95 mg/m3 air |
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Benzene |
AROMATIC ODOR
BENZENE HAS DISTINCTIVE SRP: AROMATIC ODOR HOWEVER/WARNING PROPERTIES ARE INADEQUATE SINCE 100 PPM HAS IRRITATIONRATING OF 0 & ODOR INTENSITY BETWEEN 1 & 2. 4.68 PPM In air: 4.9 mg/cu m (characteristic odor), in water: 2.0 mg/l. 61 ppm (detection); 97 ppm (recognition). Reported values range from 0.78-160 ppm.(31) |
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Methylene Chloride |
Sweet, pleasant odor, like chloroform
205-307 ppm 2.14×10 2 ppm (odor recognition in air; chemically pure sample) Odor thresholds: low= 540 mg/cu m; high= 2160 mg/cu m. Odor index: 2100 @ 20 deg C A wide range of values are reported (1.2 to 440 ppm), but detection occurs around 150 ppm and recognition around 230 ppm. |
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Vinyl Acetate Monomer |
SWEET SMELL IN SMALL QUANTITIES; PLEASANT FRUITY;CHARACTERISTIC ODOR
0.12 ppm 50% recognition threshold the conc. at which 50% of the odor panel defined the odor as beingrepresentative of the odorant being studied/: 0.40 ppm; 100% recognition threshold: 0.55 ppm. |
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Ammonia |
Colourless gas with a sharp, penetrating, intensely irritating odour
Reported values vary widely; 0.6 to 53 ppm; geometric mean: 17 ppm (detection) (27) |
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Formic Acid |
Has an intense, pungent, penetrating odour.
Reported values vary widely and are not reliable; 13-340 ppm (detection) (21); 11-13 ppm (recognition) (21); 20 ppm (100% recognition (22) |
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Hydrofluoric Acid |
Pungent, irritating, penetrating odour
0.04 ppm (0.03 mg/m3) (minimum perceptible concentration); 0.04 to 0.14 ppm (0.03 to 011 mg/m3) (3,21) |
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Methyl Mercaptan |
Rotten cabbage-1 ppb
Odour threshold ca. 2 ppb. |
Acetaldehyde has a pungent suffocating odor, but at dilute concentrations it has a fruity and pleasant odor. The odor threshold of acetaldehyde is 0.05 ppm (0.09 mg/m3).