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PubMed2001

What are the areas for further research?

The introduction of a national standard on odour measurement presents a new challenge for Australian olfactometry laboratories to meet tough new instrumental performance and panellist performance criteria. It also raises issues for end users of olfactometry results. For examples regulatory authorities may need to review the current status of odour regulations and guidelines. The paper reviews major issues pertaining to four components in odour impact assessment: measurement of odour, sampling techniques, air dispersion modelling, and the development of assessment criteria. The paper identifies and discusses the resolution of issues that could have a significant effect on the outcomes of odour impact assessment. It is hoped that the paper will provide a useful guide for industry and environmental protection authorities in the further development of an odour impact assessment procedure.

Air Pollution↗
PubMed2001

Influence of different pig housing systems on odor emissions.

The odor emissions from two different housing systems were determined during three fattening periods from October 1999 to November 2000 by analyzing weekly samples by means of dynamic olfactometry. The objects of the investigations were a standard housing system with fully slatted floor and forced ventilation (FF) compared with a kennel housing system with natural shaft ventilation (KN) in parallel operation. Only little data but with a wide range of odor emission values are available from the literature and these are difficult to compare and interpret, because of missing standards in presenting the results and experimental conditions. Therefore minimum requirements for measuring odor emissions from livestock buildings have been derived. In the scope of the measurements during the first two fattening periods (October 1999 to June 2000), no differences in odor emissions could be determined with mean values related to the livestock units (1 LU = 500 kg life weight) of 85 (FF) /87 (KN) in period A and 60 (FF) / 61 (KN) (OU/s)LU(-1) in period B. The overall range of the results of all measurements in periods A and B was 4 to 355 (OU/s)LU(-1). In period C (August-November 2000), the system FF showed higher odor emissions with 193 (28-550) compared to system KN with 105 (25-218) (OU/s)LU(-1). The air flow rates and odor concentrations at the three different naturally ventilated exhaust shafts of system KN differed considerably from each other. Odor measurement techniques with a higher temporal resolution than olfactometry are necessary to give evidence for the main factors influencing the odor formation and release.

Air Movements↗
PubMed2001

Use of electronic noses for detection of odour from animal production facilities: a review.

In the field of controlling livestock and poultry odours in the internal and external environment and in derived food products, one main obstacle is how to measure the odour in a suitable way. Olfactometry and a human panel have been used in most studies of farm odour until now. Alternatives like electronic noses are interesting considering disadvantages for olfactometry regarding cost and labour requirement. An electronic device can produce an almost instant response which is useful in many applications. Studies have shown detection of farm odour for some electronic noses and also response to odour concentrations. Other studies have shown very high odour threshold values compared to human noses. Electronic noses with a large number of sensors have been developed since a base was formed in the 1950s. The fast progress in data processing and sensor development in the latest years have made the electronic noses interesting for a large number of industrial applications in the food processing industry, as well as in other areas. Materials like manure produce a complex mixture of odorous compounds and the interaction between these creates a unique odour where no specific dominating and characterising compound seems to exist. Related to swine farms almost 200 different odorous compounds have been reported. The electronic noses can, depending on the sensitivity of its sensors, detect some compounds at lower levels than the human nose, while other compounds offensive to a human nose cannot be detected. Proper function of the electronic noses with sensitivity for the odorous gases in the application must be followed by satisfying properties regarding ageing, temperature stability, humidity and other environmental factors.

Air Pollutants↗
PubMed2004

Comparison of field olfactometers in a controlled chamber using hydrogen sulfide as the test odorant.

A standard method for measuring and quantifying odour in the ambient air utilizes a portable odour detecting and measuring device known as a field olfactometer (US Public Health Service Project Grant A-58-541). The field olfactometer dynamically dilutes the ambient air with carbon-filtered air in distinct ratios known as "Dilutions-to-Threshold" dilution factors (D/Ts), i.e. 2, 4, 7, 15, etc. Thirteen US states and several cities in North America currently utilize field olfactometry as a key component of determining compliance to odour regulations and ordinances. A controlled environmental chamber was utilized, with hydrogen sulfide as the known test odorant. A hydrogen sulfide environment was created in this controlled chamber using an Advanced Calibration Designs, Inc. Cal2000 Hydrogen Sulfide Generator. The hydrogen sulfide concentration inside the chamber was monitored using an Arizona Instruments, Inc. Jerome Model 631 H2S Analyzer. When the environmental chamber reached a desired test concentration, test operators entered the chamber. The dilution-to-threshold odour concentration was measured using a Nasal Ranger Field Olfactometer (St Croix Sensory, Inc.) and a Barnebey Sutcliffe Corp. Scentometer. The actual hydrogen sulfide concentration was also measured at the location in the room where the operators were standing while using the two types of field olfactometers. This paper presents a correlation between dilution-to-threshold values (D/T) and hydrogen sulfide ambient concentration. For example, a D/T of 7 corresponds to ambient H2S concentrations of 5.7-15.6 microg/m3 (4-11 ppbv). During this study, no significant difference was found between results obtained using the Scentometer or the Nasal Ranger (r = 0.82). Also, no significant difference was found between results of multiple Nasal Ranger users (p = 0.309). The field olfactometers yielded hydrogen sulfide thresholds of 0.7-3.0 microg/m3 (0.5-2.0 ppbv). Laboratory olfactometry yielded comparable thresholds of 0.64-1.3 microg/m3 (0.45-0.9 ppbv). These thresholds are consistent with published values.

Air Pollutants↗
PubMed2004

Hydrogen sulphide removal by activated sludge diffusion.

Odours from wastewater treatment plants comprise a mixture of various gases, of which hydrogen sulphide (H2S) is the main constituent. Microorganisms commonly found in wastewater can degrade sulphurous compounds. Therefore, the use of activated sludge (AS) for odour control offers an alternative to traditional waste gas treatment processes, such as biofilters, bioscrubbers and biotrickling filters, both in practical terms (use of existing facilities) and economically (minimal capital cost). The performance of AS diffusion as a bioscrubber for removing H2S at concentrations at 25, 75 and 150 ppmv was evaluated. Pilot-scale trials were undertaken using parallel 60-L aeration tanks and 20-L clarifier reactors at the Bedford Sewage Treatment Works, Carington, UK. Olfactometry measurements were also carried out to determine whether there was any increase in odour concentration owing to H2S diffusion. Hydrogen sulphide removal rates of 100% were obtained, with no noticeable increase in odour concentration throughout the trials as measured by olfactometry. Odour concentration was highest at the beginning of the trials and lowest during the high H2S dosing period, with similar values being obtained for test and control. It was concluded that AS diffusion is an effective bioscrubber for the removal of H2S odour.

Air Pollutants↗
PubMed2005

[Assessment of the correlation between taste and smell functioning].

UNLABELLED: There are few studies examining relationship between taste and smell. However their clinical unity is more often indicated. Smell perception abnormalities cause modification in taste of food intensity, disabling perception of taste as a consequence of taste's sniffing failure. Thus disturbances of these senses, which often commonly coexist could cause great discomfort in patients, however taste sense is estimated as less important comparing to smell sense. The aim of that study was to compare the taste perception in patients with normal smell function and patients with hyposmia and anosmia. There was analyzed correlation between the patients' subjective estimation of smell and taste senses and results of gustometry and olfactometry examinations. MATERIAL AND METHOD: there were indicated three groups of patients based on smell examination with usage of Elsberga--Levy'ego olfactometr in Pruszewicz modification. The first group included patients with normosmia, the second--patients with hyposmia or anosmia related to every smell, the third--patients with hyposmia on few smells and normal smell feeling of others. The Bornstein's method gustometry modified by us was performed for all groups. Moreover patients presented their subjective estimation of smell and taste senses. All results were statistically analyzed, taking into consideration results with alpha < or = 0.05. RESULTS: All (100%) patients with normosmia correctly identified sour, bitter and salty tastes, while only 53% of patients with hyposmia and anosmia got similar results. However 76.5% of patients from the second group subjectively estimated their sense of taste as a normal perception. CONCLUSIONS: Patients with smell disturbances significantly more often have abnormalities in taste perception than patients with normosmia and their subjective estimation of taste and smell senses is much more different than gustometry and olfactometry results.

Adult↗
PubMed1988

Anosmia associated with canine distemper.

The sense of smell in dogs infected with canine distemper virus (CDV) was examined by use of EEG olfactometry, behavioral olfactometry, and electro-olfactography. Infection with CDV was confirmed by a direct immunofluorescence technique in 8 active cases and was suggested by clinical history compatible with canine distemper 10 to 26 weeks earlier in 6 cases. Pathologic alterations of the olfactory mucosa in 3 clinically affected dogs was examined by light microscopy. Infection with CDV was found to be associated with anosmia and lack of recorded responses on electro-olfactogram in 8 of 8 dogs with clinical signs of acute distemper from naturally acquired infections. Anosmia was found in 5 of 6 dogs that had recovered from acute distemper 10 to 26 weeks earlier. The sixth dog had hyposmia, with abnormalities on the electro-olfactogram. Histologic examination was not performed on the 6 dogs that had recovered. Histologic lesions observed at necropsy in 3 dogs that had had clinical signs of acute distemper were those of subacute purulent rhinitis and atrophy of the olfactory epithelium. Altered olfactory function could be explained by mucopurulent exudate blocking odors from olfactory receptors in the acutely affected dogs, but alteration of olfactory function in the dogs that had recovered without clinical evidence of rhinitis could not be explained.

Animals↗
PubMed1987

[Assessing olfaction in general practice. A study of suitable odors].

We tested 15 substances, some of which have not so far been used for olfactometry, on a group of 200 normal adults and on 50 patients with impairment of olfaction. In the first stage the test substances were offered on strips of blotting paper. With this qualitative procedure 6 substances were found to be typical and well recognized. In a second stage these substances were tested quantitatively using the Elsberg olfactometer. This series revealed four groups with gradually differing olfactive activity. From each group one substance was accepted for definitive testing. These were: peppermint oil (strongest olfactory stimulus), benzaldehyde, orange oil and eugenol (weakest stimulus). Using this olfactory scale in the blotting paper test a rough quantitative screening of the degree of olfaction impairment should be possible, without recourse to expensive olfactometry.

Humans↗
PubMed1976

[The clinical olfactogram (author's transl)].

Clinical olfactometry is described in which patients are exposed to supraliminal stimuli of well-known types of odors. The results are then placed on a graded recognition scale as a polar coordinate system. Each clinical odor tested produces a typical recognition pattern which can easily be interpreted. Typical patterns for different conditions involving olfaction exist, and include euosmia, sensory anosmia, and respiratory anosmia. A simplified U-tube rhinomanometer can also be used, and data graphed on the same chart as for olfactometry. The procedure as described has been successfully tested on several hundred patients and controls.

Humans↗
PubMedDate not supplied

[Graphic method of recording olfactory disorders].

The authors present a method of recording results of threshold olfactometry for substances of different neuroreceptive response (olfactory, olfactive-trigeminal and olfactive-glossopharyngeal) in the form of olfactograms. The use of a unit for comparative evaluation of the olfactory function (deciodor) made it possible to get a unit horizontal zero line on the olfactogram. The authors demonstrate olfactograms of patients with various olfactory disorders. They consider that the method of graphic recording results of comparative threshold olfactometry is a valuable differential-diagnostic test.

Diagnosis, Differential↗
PubMed1998

Characterization of aroma volatiles in tomatoes by sensory analyses.

Using gas chromatography-olfactometry and aroma extract dilution analysis 34 aroma compounds were found with flavour dilution factors > or = 4. (Z)-3-hexenal, hexanal, 1-octen-3-one, methional, 1-penten-3-one and 3-methylbutanal belonged to the most odour-active aroma volatiles in fresh tomatoes. Smell, taste and aftertaste of different tomato cultivars were evaluated by quantitative descriptive analysis. By applying principal component analysis to both sensory attributes and chemical compounds (odour-active aroma volatiles, titratable acid and reducing sugars) the first three components explained 70% of the total variance. The data set was reduced to the sensory attributes intensive, tomato, sour, fruity, sweet and bitter as well as to important chemical compounds. Relations between chemical compounds and sensory attributes were found.

Chromatography, Gas↗
PubMed2002

Character impact odorants of the apple cultivars Elstar and Cox Orange.

Extracts obtained from Elstar and Cox-Orange apples (Malus var. domestica Borkh.) were screened for potent odorants by aroma extract dilution analysis (AEDA). (E)-beta-Damascenone (I), (E)-beta-damascone (II), hexanal (III), (Z)-3-hexenal (IV), (Z)-2-nonenal (V), linalool (VI), butyl acetate (VII), 2-methylbutyl acetate (VIII) and hexyl acetate (IX) were identified in Elstar and I, III-V, ethyl butanoate (X), ethyl 2-methylbutanoate (XI), 1-octen-3-one (XII), (E)-2-octenal (XIII), methional (XIV), (E)-2-nonenal (XV), eugenol (XVI) and wine lactone (XVII) in Cox Orange. The release of odorants by the cultivars was analysed by gas chromatography-olfactometry of headspace samples. Esters X and XI showed the highest odour activities in the air above Elstar apples and ester X, acetaldehyde (XVIII), 2-methylbutanol (XIX) and ethyl methylpropanoate (XX) in that of Cox Orange. Preparation of a homogenate changed the headspace composition of potent odorants. Hexyl acetate (IX) became the key odorant of Elstar and aldehydes III and IV those of Cox Orange. Quantification and calculation of odour activity values indicated I, IV, V, VII, VIII and IX as the character impact odorants of the fruit flesh of the two cultivars. Elstar contained more I, V, VII and IX and Cox Orange more IV than the other cultivar. The concentrations of VIII were similar.

Chromatography, Gas↗
PubMed2004

3-Methyl-3-sulfanylhexan-1-ol as a major descriptor for the human axilla-sweat odour profile.

This study sets out to redress the lack of knowledge in the area of volatile sulfur compounds (VSCs) in axillary sweat malodour. Sterile odourless underarm sweat (500 ml) was collected from 30 male volunteers after excessive sweating. Five strains of bacteria, Corynebacterium tuberculostearicum, Corynebacterium minutissimum, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Bacillus licheniformis, were isolated and characterised for their ability to generate an authentic axillary odour from the sweat material collected. As expected, all of the five bacterial strains produced strong sweat odours. Surprisingly, after extensive olfactive evaluation, the strain of Staphylococcus haemolyticus produced the most sulfury sweat character. This strain was then chosen as the change agent for the 500 ml of odourless underarm sweat collected. After bacterial incubation, the 500-ml sample was further processed for GC-olfactometry (GC-O), GC/MS analysis. GC-O of an extract free of organic acids provided three zones of interest. The first was chicken-sulfury, the second zone was onion-like, and the third zone was sweat, clary sage-like. From the third zone, a new impact molecule, (R)- or (S)-3-methyl-3-sulfanylhexan-1-ol, was isolated and identified by GC/MS, MD-GC, and GC AED (atomic emission detector). (S)-3-methyl-3-sulfanylhexan-1-ol was sniff-evaluated upon elution from a chiral GC column and was described as sweat and onion-like; its opposite enantiomer, (R)-3-methyl-3-sulfanylhexan-1-ol, was described as fruity and grapefruit-like. The (S)-form was found to be the major enantiomer (75%).

Adult↗
PubMed1999

Changes in olfactory responsiveness by the domestic chick after early exposure to odorants.

There is increasing evidence that odorants are important in the formation of attachments by the domestic chick, Gallus gallus domesticus. We investigated whether early exposure to nonaversive odorants altered the responses of 1-day-old chicks to a number of odorants from naturalistic sources, including feathers and faeces of adult chickens, wood litter and food (chick starter mash). The odorants were delivered by dynamic olfactometry, in which air containing different concentrations of each odorant was presented separately to individually housed chicks together with a small, coloured bead at which they could peck. When tested with a faecal odorant, but not the other odorants, control chicks, incubated and reared under standard conditions, shook their heads more but their pecking responses did not vary for any of the odorants tested. Chicks that had been exposed to a moist-food odorant from embryonic day 20 to 18 h posthatching and tested with odorants from either moist or dry food pecked less than controls but shook their heads the same amount. Early exposure to the moist-food odorant did not affect responses to the odorants of feathers or faeces. Chicks apparently learn about their olfactory environment during the later part of incubation and in the early posthatching period and the memory formed alters behaviour on day 1 posthatching. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1989

Influence of the D-2 dopamine receptor agonist quinpirole on the odor detection performance of rats before and after spiperone administration.

The influence of five doses of the D-2 receptor agonist quinpirole (0.025, 0.05, 0.075, 0.10, and 0.20 mg/kg IP) on the odor detection performance of 21 adult male Long Evans rats was assessed using high precision olfactometry and a go/no-go operant task. Additionally, ten rats were pre-treated with the D-2 receptor antagonist spiperone (0.62 mg/kg IP) and their performance monitored following quinpirole administration. Treatments were administered every third day in a counterbalanced order, with the quinpirole injections occurring 15 min before, and the spiperone injections 35 min before, the 260-trial test sessions. Quinpirole injection resulted in a dose-dependent decrease in odor detection performance, as measured by the percentage of correct trials and by the non-parametric signal detection sensitivity index SI. Prior treatment with spiperone eliminated these effects. Dose-related influences of quinpirole on (a) the average latency to initiate a detection response (i.e., the S + response latency), (b) the total session duration, and (c) the number of aborted trials were also eliminated or greatly attenuated by prior spiperone injection. These results suggest that D-2 receptors may be involved in the modulation of odor detection performance and related behaviors.

Acetates↗
PubMed1987

Odor detection performance of rats following d-amphetamine treatment: a signal detection analysis.

The effects of d-amphetamine sulfate (0.2, 0.4, 0.8, and 1.6 mg/kg SC) on the odor detection performance of 16 adult male Long Evans rats was assessed using high precision olfactometry and a go/no-go operant signal detection task. The drug or saline was administered every 3rd day in a counterbalanced order, with the injections occurring 5 min before each 260-trial test session. Relative to saline, enhanced detection performance to the target stimulus (ethyl acetate), as measured by a non-parametric signal detection index (SI), was observed following administration of 0.2 mg/kg of the drug, whereas decreased detection performance was observed following administration of 1.6 mg/kg of the drug. Significant increases in the responsivity index (RI) occurred at the higher drug dosages for the lower odorant concentrations. In addition, small but statistically significant increases in the latency to respond in the presence of the odor (i.e., S+ response latency) were present at the higher drug dosages. Overall, these data suggest that (a) odor detection performance is enhanced by low doses of amphetamine, (b) odor detection performance is depressed by moderate doses of amphetamine, and (c) drug-related alterations in response criteria occur following the administration of moderate doses of amphetamine.

Animals↗
PubMed2003

A female-specific attractant for the codling moth, Cydia pomonella, from apple fruit volatiles.

Host plant-derived esters were investigated as potential female-specific attractants for the codling moth (CM), Cydia pomonella (L.), a key pest of apples worldwide. The behavioural effects of single and combined volatile compounds and of a natural odour blend were examined using olfactometry and wind-tunnel bioassays. The apple-derived volatile butyl hexanoate attracted mated females while it was behaviourally ineffective for males over a dosage range of more than three orders of magnitude in olfactometer assays. Female CM preferred this kairomone to the headspace volatiles from ripe apples. Both no-choice and choice trials in the wind-tunnel suggested that female moths might be effectively trapped by means of this compound. In contrast, headspace volatiles collected from ripe apple fruits as well as a blend containing the six dominant esters from ripe apples were behaviourally ineffective. A female-specific repellency was found for the component hexyl acetate in the olfactometer, but this ester had no significant effect in the wind-tunnel. Butyl hexanoate with its sex-specific attraction should be further evaluated for monitoring and controlling CM females in orchards.

Animals↗
PubMed1998

SKF 38393 enhances odor detection performance.

The purpose of this study was to determine the influence of the D1-selective partial agonist SKF 38393 on the odor detection performance of rats using high precision olfactometry and a go/no-go operant task. Previous studies have found that the D2 receptor partial agonist quinpirole decreases such performance, but the influences of D1 receptor activation are unknown. In experiment 1, such detection performance to the odorant ethyl acetate was enhanced by SKF 38393, relative to saline, in male rats at 7.5 and 10.0 mg/kg i.p. dose levels, but not at the lower doses of 1.0, 2.5, and 5.0 mg/kg. In experiment 2, this enhancement was replicated at the 7.5 and 10.0 mg/kg doses and was shown to occur at the 12.5 mg/kg dose as well. In experiment 3, similar enhancement was shown for the odorant eugenol in female rats at the 7.5, 10.0 and 12.5 mg/kg doses, suggesting this effect is neither sex-specific nor confined to the odorant ethyl acetate. In experiment 4, a 0.025 mg/kg dose of the D1 receptor antagonist SCH 23390 depressed the enhancement produced to ethyl acetate by 7.5 mg/kg SKF 38393 to control levels. Overall, these data demonstrate that, in contrast to quinpirole, SKF 38393 improves odor detection performance in the rat and that this phenomenon can be attenuated by the D1 receptor blocker SCH 23390.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗