Foul Gas Research Articles

Research on electronic nose for compound malodor recognition combined with artificial neural network and linear discriminant analysis

The foul odor of foul gas has many harmful effects on the environment and human health. In order to accurately assess this impact, it is necessary to identify specific malodorous components and levels. In order to meet the qualitative and quantitative identification of the components of malodorous gas, an electronic nose system is developed in this paper. Both principal component analysis (PCA) and linear discriminant analysis (LDA) were used to reduce the dimensionality of the collected data. The reduced-dimensional data are combined with a support vector machine (SVM) and backpropagation (BP) neural network for classification and recognition to compare the recognition results. Regarding qualitative recognition, this paper selects the method of LDA combined with the BP neural network after comparison. Experiments show that the qualitative recognition rate of this method in this study can reach 100%, and the amount of data after LDA dimensionality reduction is small, which speeds up the pattern speed of recognition. Regarding quantitative identification, this paper proposes a prediction experiment through Partial least squares (PLS) and BP neural networks. The experiment shows that the average relative error of the trained BP network is within 6%. Finally, the experiment of quantitative analysis of malodorous compound gas by this system shows that the maximum relative error of this method is only 4.238%. This system has higher accuracy and faster recognition speed than traditional methods.

The important role of tricarboxylic acid cycle metabolism pathways and core bacterial communities in carbon sequestration during chicken manure composting

As a kind of livestock manure, chicken manure (CM) was rich in organic matter and microorganisms. However, a large amount of foul gas discharged by its random stacking not only threatened the environment, but also caused harm to human health. In view of the serious carbon loss and the unclear action mechanism of microbial community on carbon metabolism during CM composting, the effect of adding regulators on the sequestration of organic carbon was explored. Therefore, the purpose of this study was to explore the regulation mechanism of adding tricarboxylic acid cycle (TCA cycle) regulators on the core carbon metabolism pathway during CM composting. The results showed that the adenosine triphosphate (ATP) and malonic acid (MA) slowed down organic carbon degradation, resulting in lower carbon loss rate, which were 64.99% (CK), 62.35% (MA), and 61.26% (ATP) in each treatment. By comparing the abundance and structure of the carbon-related bacterial communities in different treatments, it was found that adding ATP and MA not only reduced the bacterial community abundance, but also tended to be similar in bacterial community composition. Moreover, the microbial specificity related to carbon metabolism pathway was enhanced, while the related gene expression and gene abundance were weakened. The regulation of TCA cycle metabolism pathway was confirmed to be the main way to improve organic carbon content. These findings revealed the positive effects of ATP and MA on carbon fixation from the perspective of gene metabolism.

Experimental study on air pressure variation in a horizontal pipe of single-stack drainage system.

The water trap seal under the sanitary appliances is the primary defense against the ingress of foul gases and odors. However, research on air pressure variation in a horizontal pipe of a single-stack drainage system is very limited. Thus a physical model study was conducted to investigate the air pressure variation in a horizontal pipe. Four parameters were studied that affect the pressure variation; that is, water flow rate, inlet height, ventilation condition and outlet condition. When the top of the vertical drainage stack and the outlet were fully open to the atmosphere, the flow in the horizontal pipe changed from free surface flow to slug flow at certain times. The mean values and magnitudes of pressure fluctuation at measuring points on the horizontal pipe increased with Qw but decreased along the horizontal pipe. The inlet height had relatively small influence on the pressure variation. Three ventilation conditions; that is, top fully open, half open and sealed, were tested, and a choking flow was formed in the vertical drainage stack and the pressure in the horizontal pipe decreased under the top sealed condition. Three outlet conditions; that is, outlet fully open, half submerged and fully submerged, were tested. The pressure in the horizontal pipe increased significantly under the outlet fully-submerged condition, which should be avoided in the actual operation by careful designing.

Performance Evaluation of Air Pollution Forecast Models

Background: Air pollution affects both the health of living being and the materialistic resources. Amid the development of anthropogenic methods and machines, atmosphere has turned as a sink for foul gases and disorderly energy. Air pollutant discharges have deteriorated the natural composition of air in atmosphere at spatial manner. Method: The resulting losses from air pollutants can be minimized either by control at source (through air pollution control devices) or by diverting the receptor from pollution prone area. The second option requires an exact estimation of air pollutant’s concentration, which can be done by use of air pollution forecast models. There are many simulation models for forecasting the air pollutant concentration at any place. However, the results of these models are questioned many times because of inappropriate forecasting. In this paper author proposes a comprehensive multi-criteria process based upon statistical formulae for the evaluation of the performance of Air Pollution Forecast Models. Results: The performance of Air Pollution Models can be judged by error analysis, comparison of forecasted and observational data, use of statistical performance measurements and criteria. All these techniques are discussed for their suitability and guiding the modeler to select the optimal criteria for best model performance. Conclusion: The selection and use of specific evaluation criteria and their ability to interpret the results varies with the study area, prevailing meteorological conditions, formulation of model structure and behaviour of observed data and simulation results. A suitably selected performance criteria help in designing the best deliverable air pollution forecast model. Keywords: Concentration, forecasting, efficiency, error, modelling, dispersion, statistical, turbulence.

Removal of CH3SH with in‐situ generated ferrate(VI) in a wet‐scrubbing reactor

AbstractBACKGROUNDA wet scrubbing process with in‐situ electro‐generation of ferrate(VI) has been developed for removing odour from foul gas in wastewater treatment plants. In this process, methyl mercaptan (CH3SH) in synthetic gas is removed through absorption and oxidation by contacting the gaseous stream with aqueous NaOH electrolyte that offers in‐situ generation of ferrate(VI).RESULTSThe process parameters including electrolyte concentration, applied current density, initial CH3SH concentration, gas flow rate and gaseous CH3SH compositions were investigated to determine the best operating conditions and design parameters for a scale‐up design. Under all the experimental conditions, gaseous CH3SH was completely removed by the wet scrubbing process at room temperature and atmospheric pressure. The process proved to be quite effective for dissolved CH3S‐ degradation under the optimum experimental condition at the NaOH concentration of 6 mol L–1, current density of 2.22 mA cm‐2 and CH3SH loading below 30 g m‐3 h‐1. A very short contact time of 0.06 s between the gas and the liquid phases was achieved in this in‐situ ferrate(VI) generation reactor.CONCLUSIONSThis process is effective for CH3SH control, and holds great promise for industrial applications due to its high efficiency, simplicity and stability. © 2013 Society of Chemical Industry

The Design and Operation of Yongin Feces and Livestock Wastewater Complex Treatment System in Korea

The feces and livestock wastewater is characterized with complicated and high level in pollutant and foul odor, great change with loading. Humus activated sludge process with anaerobic-intermittent aeration mode were adopted to treat feces and livestock wastewater complex. The design and operation result showed that the process could remove effectively high concentration organic matter, TN,TP and SS, no foul gas release in residual sludge and during operation, the system has strong tolerance to the high hydraulic load through adjusting aeration period and reflux ratio. The feces and livestock treatment in China can draw lessons from the Yongin feces and livestock wastewater complex treatment system in Korea

The Research on the Airflow Organization of Residential Kitchen and how to Introduce Make-up Air

Discusses how to making up air to balance indoor air, eliminate the traditional system defects, through in the hearth (under the smoke exhaust ventilator) additional secondary air tuyere. Using the CFD--fluent6.2 simulation software simulates the airflow organization of the kitchen exhaust system if making up air . Analyze the kitchen indoor airflow velocity distribution, and the pressure distribution in the different condition. Setting sizes for 0.06 ~ 0.10 m2 of secondary air tuyere, fill with air 0.162 ~ 0.184 kg/s ,it can avoid lampblack pollutants spilling effectively, reduce the operating energy consumption. After making-up air the kitchen remains negative state. Under the action of differential pressure, outdoor air is sucked into the kitchen so as to achieve the result, form reasonably airflow organization, meet exhaust requirements, get rid of foul gas effectively.

Power generation from waste heat in a food processing application

In this paper, the potential of recovering waste heat from the fryer section and exhaust stream sent to the stack of a typical potato crisps or chips manufacturing plant and using the heat to drive an Organic Rankine Cycle (ORC) system for power generation has been presented. Five different ORC system Options (A, B, C, D and E) were considered. The first two options (A and B) make use of the waste heat from the foul gas and exhaust to stack respectively for power generation using a single ORC system each while the third option (option C) makes use of a novel dual heat source single ORC system where the low temperature waste heat from the foul gas is used to provide preheating and the high temperature waste from the exhaust to the stack used to provide the evaporation. Option D also shows a dual heat source ORC system where the high temperature waste heat to the exhaust stack is used to provide the preheating while the lower temperature foul gas is used for the evaporation (reverse of option C in terms of waste heat usage) while option E makes use of a reheat cycle where the waste heat from the foul gas is used to provide the reheating of the working fluid exiting the turbine. In terms of waste heat usage, the combination of options A and B can be compared with options C, D and E. The simulation result shows that in terms of net power generation, cooling water requirement, and working fluid (R245fa) requirement, the combination of Options A and B gives the best power generation result and this is similar as the result produced by Option C. Following option C is option E which gave a better result than option D. The entropy generation analysis showed that the entropy generation is inversely proportional to the power output. It was also observed that the net power generation for the ORC configuration adopted in this paper (option C) meets the average daily power requirement of the crisps manufacturing process as well as 98.58% of the daily peak power requirement. ► We model and optimised different ORC configurations for power generation from waste heat in crisps manufacturing plant. ► We carried out second law analysis of the different configurations. ► We selected the configuration which will be most economical for power generation from waste heat in crisps manufacturing plant.

Long-Term Outcome of Rifaximin Therapy in Non-constipation Irritable Bowel Syndrome

To the Editor, The article by Pimentel et al. [1] on rifaximin retreatment of irritable bowel syndrome (IBS) was read with interest because of the shortage of published long-term data in this area. However, there are two concerns with this report. First, the patients in the study were recruited from a university medical center and therefore may not be representative of a community practice patient population. Second, use of prophylactic medication was not outlined, and this could influence the rate of IBS recurrence after rifaximin therapy. To investigate these issues, a retrospective chart review of patients with diarrhea-predominant or alternating IBS from a community-based gastroenterology center was performed. Medical charts of patients with non-constipation IBS and suspected small intestinal bacterial overgrowth who received rifaximin 800–1,800 day for 10–14 days between 2005 and 2011 were captured from an electronic database based on medical codes for bacterial overgrowth (n = 95). Small intestinal bacterial overgrowth was suspected in patients with an abnormal rise in hydrogen and/or methane above 20 ppm from baseline at or before 90 min if diagnosed after 2009 or at or before 180 min if diagnosed before 2009 or in patients who displayed other clinical features suggestive of the disorder (e.g., postprandial distention and foul gas). In patients who required rifaximin retreatment for recurrent symptoms, most (65%) received the same treatment regimen as prescribed initially. Seventy patients (74%) had an adequate response to initial rifaximin treatment (i.e., had significant relief of IBS symptoms based on clinical notes and patient reporting after rifaximin therapy). Of these patients, 49 (70%) received C1 retreatment courses of rifaximin during a mean follow-up of 3.5 years (range 0.75–6.4). Response to rifaximin retreatment and the durability of the response did not decline with increasing number of retreatment episodes (Table 1). Seven adequate responders (9%) received rifaximin without initial prophylactic therapy. Of these, four patients did not receive prophylactic therapies during a mean of 3.1 years (range 0.5–5) and required a mean of 2 (range 1–3) additional rifaximin treatments. Sixty-six patients (94%) received rifaximin in combination with C1 prophylactic therapy administered singly: tegaserod (n = 13), erythromycin (n = 45), naltrexone (n = 26), and probiotics (n = 20). Long-term, low-dose rifaximin was required to maintain remission in seven patients because other prophylactic therapies were ineffective. Nineteen of the 66 initial adequate responders who received prophylactic therapy experienced sustained symptom improvement during a mean follow-up of 2.7 years (range 0.4–12.2). Of the 49 patients who had C1 rifaximin retreatment while receiving prophylactic therapy, an average of 2.2 rifaximin retreatments was required (range 1–7) during a mean of 3.8 years (range 0.75–6.4). These data demonstrate that the majority of patients (74%) with non-constipation IBS in a community gastroenterology practice experienced relief of IBS symptoms after their initial course of rifaximin and that most responded to rifaximin retreatment. These observations are L. B. Weinstock Department of Gastroenterology, LLC, St. Louis, MO, USA

The Research on the Airflow Organization of Residential Kitchen and how to Introduce Make-Up Air

This thesis analyzes the exhaust system of residential kitchen existing problems of indoor air quality. Discusses how to making up air to balance indoor air, eliminate the traditional system defects, through in the hearth additional secondary air tuyere through using the CFD----fluent6.2 simulation software simulates the airflow organization of the kitchen exhaust system if making up air . Analyze the kitchen indoor airflow velocity distribution, and the pressure distribution and velocity vector in the different condition. Under the action of differential pressure, outdoor air is sucked into the kitchen so as to achieve the reasonably airflow organization and get rid of foul gas effectively.

Ozonation of Odorous Compounds in Gases Emitted from Rubber Processing Industries

This study aimed at the removal of odorous compounds in gases emitted from rubber processing industries. Simulated odorous gas for test was prepared by mixing fresh air and an odorous gas drawn from an oven in which a sample of rubber powder was kept either at 160°C (for a thermal plastic rubber) or 200°C (for a thermal setting rubber). The prepared odorous gas was then premixed with a definite amount of ozone-enriched air and introduced into a contact system. The contact system consists of two sieve-plate columns connected in series and each column has four 1-L chambers. Depending on with or without introducing circulating scrubbing water into the columns, the oxidation reaction could be either wet or dry one. Results indicate the wet oxidation got better performances than the dry one. The former got 97 and over 90% removal of VOCs (volatile organic compounds) and odorous intensity removal, respectively, with the operation conditions of initial ozone concentration 4.0 ppm, THC (total hydrocarbon) concentrations 6.5–10.3 ppm (methane equivalent), oxidation temperature 37.3°C, gas empty bed retention time (EBRT) 12 s, and liquid/gas rate ratio 0.01 m3/m3. With conditions similar to those cited above, odor concentration (dilutions to the threshold, D/T) in the test gas could be reduced from 1,738–3,090 to 31–98 with EBRTs of 11.4–14.5 s. Activated carbon is effective for both physical and chemical removals of residual VOCs, odorous compounds, and ozone in the effluent gas from the ozonation system. Economical analysis indicates that around US$ 0.16 is required for treating 1,000 m3 of the tested foul gas by the proposed ozonation process.

Characteristics of air pressure fluctuations in high-rise drainage stacks

Maximum air pressure in a drainage stack can deplete the appliance water trap seals that prevent the ingress of foul gases and odors into a habitable space. This study investigates the air pressure fluctuation frequency, as well as the maximum and average air pressures with their respective standard deviations, in a 38 m high drainage stack of a full-scale experimental tower under steady flow conditions of flow rates 1 Ls −1 to 4 Ls −1 discharging at a height between 15 m to 33 m above the stack base. Mathematical expressions are proposed to correlate the maximum air pressure with the probability density function of the data measured. The average prediction and the maximum under-prediction of the absolute peak pressure were determined with the margin of error taken within certain confidence levels. It was demonstrated that water seal failure would likely be occurred at some heights below the discharge locations. The outcome enhances the understanding of the characteristics of air pressure fluctuation within a drainage stack of a high-rise building.

Photocatalytic Oxidation of Methyl Mercaptan in Foul Gas for Odor Control

Methyl mercaptan (CH3SH) is a representative odorous pollutant from various odor emission sources such as sewage and municipal solid wastes. This study confirms that CH3SH in a synthetic foul gas can be effectively decomposed by UV-C (<280 nm) photolysis using germicidal lamps, but is resistant to destruction under UV-A (365 nm) irradiation using black-light lamps. This study also demonstrates that CH3SH in foul gas can be successfully degraded by photocatalytic oxidation under UV-A irradiation using TiO2-based photocatalysts. In this study, two new catalysts, NH4+-modified TiO2 (NH4+-TiO2) and SO42--modified TiO2 (SO42--TiO2), were prepared by a precipitate-refluxing method and a hydrothermal method, respectively. These two catalysts as well as the commercially available catalyst Degussa P25 (P25-TiO2) were used for the photocatalytic degradation of CH3SH. It was found that the NH4+-TiO2 catalyst achieved a better performance than P25-TiO2, whereas SO42--TiO2 demonstrated a poorer performance. The high photocatalytic activity of NH4+-TiO2 for CH3SH degradation results from its basic characteristics and the presence of an ammonium (NH4+) group on the NH4+-TiO2 catalyst surface. The photocatalytic degradation of CH3SH was further studied using the P25-TiO2 catalyst under different experimental conditions. The experimental results showed that catalyst loading, relative humidity, and initial concentration could influence the efficiency of CH3SH photocatalytic degradation significantly. It was found that a catalyst loading of 3.93 mg cm-2 and a relative humidity of 43% are two essential factors for achieving the best performance under these experimental conditions. This work provides new insights into the removal of a sulfur-containing organic substance (CH3SH) from the gas phase by both photolysis and photocatalytic oxidation processes.

Multi-zone modeling of probable SARS virus transmission by airflow between flats in Block E, Amoy Gardens

More than 300 residents of a private high-rise housing estate were infected with severe acute respiratory syndrome within a short period during the 2003 epidemic in Hong Kong. The outbreak occurred after the identified index patient visited a flat on a middle floor in Block E of the Amoy Gardens estate on two nights. Approximately 45% of the subsequently infected people resided in Block E, while the other 55% of infected cases mainly resided in six other blocks close to Block E. The distribution of the infected flats in Block E conformed to a non-uniform spatial pattern. Probable environmental causes for airborne transmission associated with the air movements between flats in Block E are identified. The well-established multi-zone airflow modeling method was used to analyze the virus-laden bio-aerosol dispersion between flats through door and window leakage areas in Block E under six different scenarios. The distribution of infection risk in Block E matched with the virus concentrations in flats predicted with the use of multi-zone modeling. Our study shows the importance of ventilation design in high-rise residential apartments. The present study on the Amoy Gardens outbreak presented a scenario in which crowded living spaces might lead to infection disasters. There is a need to improve the current sanitary drainage design and maintenance standards to avoid any leakage of foul gas into the indoor environments. Our study revealed the need for a review of indoor air quality and ventilation design in buildings including offices, homes and hotels. The study has implications to public health in, for example, the control of other airborne respiratory infectious diseases such as influenza, and in bio-terror safety in buildings.

P0545 KLEBSIELLA OXYTOCA(KO) INFECTION, A POSSSIBLE CAUSE OF COLITIS IN INFANTS PRESENTING WITH MILK INDUCED (???ALLERGIC???) COLITIS(MIC)

Introduction: MIC is frequently diagosed clinically in infants when they present with rectal bleeding, diarrhea and varying degrees of pain. They respond to the change of protein in their formula or to total milk protein elimination in the mother’s diet in breast fed infants. Stool cultures are often not done most likely because the infections are asssumed to be uncommonin this age group. Endoscopy, biopsy and dietary challanges are not usually done. Recently, Y. Davies et al presented an older infant with chronic diarrhea, abdominal distension and abdominal pain. (VSL#3 Satellite Symposium NASPGHAN meetings Montreal,Oct 2,2003) The pateint was shown to have an enteric infection with toxigenic strain of Ko. Ko was cultured from the stool. The toxin was demonstrated. The patient responded to probiotic therapy. Here we report two infants who presented with apparent MIC and their stool cultures grew Ko. Methods: All stool cultutres from author’s(BB) practice done in the last 3 yrs were reviewed and two were found to be positive for Ko. Case Summaries: 1. L.A., a full term product of normal pregnancy and delevery presented at 4 wks of age with severe pains during feeding, irrirtability and foul gas with variable response to milk protein elimination in mother’ diet and conservative management. 3 wks later he developed severe diarrhea with cramping with blood flecks and mucus. Milk induced colitis was suspected; stool c/s grew Ko. 2. O.H. a full term product of normal pregnancy and delivery presented with 3 month history of intermittent rectal bleeding stariting at 10 wks of age with appparent temporary response to milk protein elimination in the mother’ diet and then soy protein elimination. Stools became more bloody with mucus. Stool c/s grew Ko. Results: Ko is generally considered a saprophyte in the bowel. On rare occassions it has been implicated to cause antibiotic induced diarrhea or colitis. Clinically isolated strains of Ko are shown to produce a low molecular weight cytotoxin that causes hemorrhagic colitis in rabbit ileal loop model and cytotoxic changes in cell cultures. Conclusion: This to our knowledge is the first report of assosciation of Ko with apparent MIC. Epidemiological and prospective clinical studies with the appropriate bacteriologic and toxin studies are needed to further define their role in MIC and are planned. Stool cultures should be considered in MIC and should include culture for all potential and rare pathogens, because of the relatively depressed immune state of the newborn. Reference(S): none

Control and suppression of air pressure transients in building drainage and vent systems

Air pressure transients propagate within building drainage and vent systems due to the unsteady nature of the network flows. These low-amplitude transients may deplete the appliance water trap seals that prevent ingress of foul gases and odours into habitable space. The simulation of transient propagation and trap seal response is achieved via the method of characteristics solution of the St. Venant equations. The application of transient control and suppression methodologies to control both positive and suction pressure trap seal loss is demonstrated and the importance of trap seal retention to prevent cross contamination via the drainage network is emphasised.

Joyfully, but Briefly

I couldn't draw because I hated the model, she was aggressively fat. She looked like she'd been floating in a river for 3 days. To be sure I prodded her with a long stick and she rolled over and leaked a foul gas that spread along the ground crippling insects. A pony dragged a carriage through the park disconcerting me joyfully, but briefly. The model crawled back into her stance, an aura of art around her, I couldn't tap into it. It smoked and drifted up to the trees, they sucked it in their lungs. They're called leaves, but they're lungs.

Hydrogen sulphide and volatile fatty acid removal from foul air in a fibrous bed bioreactor

Odour control in Hong Kong has been addressed as an important issue by the authorities, since odour pollution is generated from many sources including wastewater treatment plants. Although a number of existing technologies are available for odour abatement and control, biological technique is still more attractive due to its low operating cost and ease of maintenance. A newly innovated fibrous bed bioreactor with twin columns was specially designed and constructed in our laboratory, in which an inner column was centred in an outer column. The bioreactor was fully filled with water in order to absorb the odorous components from foul gas and also contained both suspended and attached biomass to degrade the absorbed odorous pollutants. In this study, hydrogen sulphide (H2S) and butyric acid (C4H8O2) were used as odorous components and successfully removed from synthetic foul gases. Many factors affecting the H2S and butyric acid removal efficiency and maximum elimination capacity, such as pH of water solution, gas flow rate and its fluctuation, and sulphate content in solution have been studied. The experimental results demonstrated that the reduction rates of 97.8% for H2S and 99.9% for butyric acid were achieved in this experimental condition. It is proved that this bioreactor was a compact odorous gas treatment system with an application potential for treating foul air with high odour strength and low airflow rate such as the offensive gases from sludge treatment processes in a wastewater treatment plant.

Hydrogen sulphide and volatile fatty acid removal from foul air in a fibrous bed bioreactor

Odour control in Hong Kong has been addressed as an important issue by the authorities, since odour pollution is generated from many sources including wastewater treatment plants. Although a number of existing technologies are available for odour abatement and control, biological technique is still more attractive due to its low operating cost and ease of maintenance. A newly innovated fibrous bed bioreactor with twin columns was specially designed and constructed in our laboratory, in which an inner column was centred in an outer column. The bioreactor was fully filled with water in order to absorb the odorous components from foul gas and also contained both suspended and attached biomass to degrade the absorbed odorous pollutants. In this study, hydrogen sulphide (H2S) and butyric acid (C4H8O2) were used as odorous components and successfully removed from synthetic foul gases. Many factors affecting the H2S and butyric acid removal efficiency and maximum elimination capacity, such as pH of water solution, gas flow rate and its fluctuation, and sulphate content in solution have been studied. The experimental results demonstrated that the reduction rates of 97.8% for H2S and 99.9% for butyric acid were achieved in this experimental condition. It is proved that this bioreactor was a compact odorous gas treatment system with an application potential for treating foul air with high odour strength and low airflow rate such as the offensive gases from sludge treatment processes in a wastewater treatment plant.

Irradiation‐induced off‐odour in chicken and its possible control

1. Volatiles isolated from irradiated raw chicken were analysed by gas chromatography (GC) in conjunction with olfactory assessment of the effluent carrier gas to locate compounds with strong smells. 2. Sixteen odours of differing intensities were registered, some, but not others, coinciding with recognisable GC peaks. Identifications were made on the basis of retention data, mass spectrometric information and odour quality agreement. 3. Dimethyltrisulphide was found to be the most potent and obnoxious compound (foul gas, sulphurous), followed by cis-3- and trans-6-nonenals (soapy), oct-1-en-3-one (mushroom) and bis(methylthio-)methane (foul). With the exception of oct-1-en-3-one, none of these compounds has been reported before in irradiated raw chicken. 4. alpha-Tocopherol and ascorbic acid induce stability in tissues in vivo and post mortem. Chickens were reared on diets supplemented with high concentrations (800 mg/kg food) of each of these vitamins. Yields of irradiation volatiles from the tissues of these birds were very much reduced, compared to yields from similar tissues from birds fed unsupplemented diets. 5. Concomitantly with the reduced yield of volatiles, less odour was associated with the samples when analysed by GC-olfactory analysis. 6. The use of enhanced concentrations of the two vitamins in combination in the diet of poultry may provide a means of controlling development of off-odour in irradiated raw chicken, thus improving acceptability to the consumer.