Odor Units Research Articles

반월.시화공단 주변 주거지역의 악취현황 및 황화합물의 체감도

This study was carried out to investigate the characteristics of fourteen odor compounds from a total of 10 sampling sites in residential areas around Banwol-Sihwa industrial complex. The measurement data are analyzed and compared with sensation of odor unit. Only a hydrogen sulfide out of four sulfur compounds was quantified above the detection limit (0.06 ppb) in the residential area around Banwol industrial complex with leather companies and a sewage treatment plant. The concentrations of VOCs were higher than those measured from a big city, and styrene showed the relatively high concentration from all sampling sites (<TEX>$2.1{\sim}37.8\;ppb$</TEX>). In the case of carbonyl compounds, acetaldehyde was found most frequently with the mean of 3.97 ppb, and its concentration difference was not significant between Banwol and Sihwa industrial complex. Of the nitrogen compounds, ammonia was measured at the relatively high concentration from all the sampling sites (<TEX>$12{\sim}707\;ppb$</TEX>), and a trimethylamine was found at the odor threshold level (0.1 ppb). The concentrations of styrene and ammonia showed relatively seasonal variation, the concentration of styrene in summer was five times higher than that in autumn, the concentration of ammonia in autumn was two times higher than that in summer. However other odorous compounds did not show such strong seasonal variation. Odor-concentration relationship between odor unit and <TEX>$H_{2}S$</TEX> concentrations from industrial sources was examined and used as odor sensation evaluation, and thus the neighbourhood odor complaints maybe caused during the four seasons from the results.

Evaluation of Measured And Predicted Odor Concentrations around A Meat Packaging And Rendering Plant

Odor levels around a meat packaging and rendering plant were predicted by using the CALPUFF dispersion model. The product of olfactometrically measured odor concentration and volumetric flow rate of the stack gas stream was used as emission strength of the source. Ambient odor levels were also measured at two sites downwind of the plant by olfactometry. This was possible, as odor concentrations were above 50 odor units per cubic meter (OU m −3 ), and this means that the concentrations were always exceeding the minimum 10 OU m−3 that can be safely measured by this technique. Odor samples were taken consecutively at two sites downwind of the source with 10 s duration each. These sampling sites were chosen so that they had continuous odor nuisance problems, which indicated that they were near the centerline of the plume. Between samples 10-s intervals were necessary to prepare the sampler for the next sampling bag connection. The overall sampling period was 10 min each at the two sites. Meteorological measurements were carried out throughout the odor sampling process at the sites. Wind direction and speeds were recorded at the end of each sampling and used in predictions made using the model. Predicted results were compared with the odor measurements carried out on the samples. Measured and predicted odor concentrations were tested to see the degree of correlation. The measured and predicted results at such very short averaging times correlated well, with a good agreement between the two series.

Comparison of Headspace Solid-Phase Microextraction with Simultaneous Steam Distillation Extraction for the Analysis of the Volatile Constituents in Chinese Apricot

Volatile constituents in fully mature fruits of apricot ( Prunus armeniaca L.) cultivar Xinshiji were extracted using headspace solid-phase microextraction (HS-SPME) and simultaneous steam distillation extraction (SSDE) and then analyzed using capillary gas chromatography and gas chromatography-mass spectrometry. A total of 70 components were identified by HS-SPME, including 20 esters, 19 hydrocarbons, 5 alcohols, 5 ketones, 4 acids, 4 lactones, 3 aldehydes, and 10 miscellaneous components, with the esters being the dominant constituent. On the basis of the odor unit values, it is believed that the following compounds probably contributed to the fresh apricot odor: hexyl acetate, β-ionone, butyl acetate, (E)-2-hexcnal, linalool, limonene, γ-decalactone, and hexanal. A total of 49 components were also detected by SSDE, including 13 hydrocarbons, 9 alcohols, 7 aldehydes, 9 esters, 4 ketones, 4 lactones, 2 acids, and 1 miscellaneous component, of which the monoterpene alcohols were the dominant constituents. It could be judged from the odor unit values that the following compounds were the major contributors to boiled apricot aroma: β-ionone, linalool, hexyl acetate, γ-dodecalactone, γ-decalactone, (E)-2-hexenal, hexanal, γ-octalactone, phenylacetaldehyde, butyl acetate, limonene, α-terpineol, and δ-decalactone. The results show that HS-SPME is a simple, rapid, and solvent-free method, which is an alternative to the classical SSDE.

Improvement of Odor Intensity Measurement Using Dynamic Olfactometry

Odor intensity reveals a dose-effect relationship between inhaled odor and perceived odor sensation by the receptors, while odor concentration reflects the odor strength at the emission sources. The study reports significant improvements in experimental procedures in establishing the odor concentration-intensity (OCI) relationships using a newly developed digital olfactometer. The improvements in experimental procedures have been made to meet the requirements of both the VDI guideline 3882.1 and the European standard (EN13725). Several areas which could affect the reliability of the results have been identified in some similar studies. The latest digital olfactometer was calibrated automatically to ensure accurate and repeatable dilution ratios. Cross contamination has been eliminated through the instrument design and extensive cleaning procedures, making random presentation possible. Stringent panelist screening and continuous performance monitoring ensures consistent sensitivity of the panel. The extension of odor intensity category to temperature sensation gives a reference to assist judgments of perceived odor sensation. The Dyna-Scent calculation method has simplified odor intensity calculation and can be applied to many odor samples. A total of 38 odor samples from three alumina refinery sites and two sewage treatment plants were collected for analysis. The results have confirmed the efficiency of the olfactometer. Distinct Odor Concentrations (DOCs) were calculated for each sample using both VDI and DynaScent methods. A student t test on two major odor types confirmed that there are no significant differences between two methods. The study has shown the DOCs for refinery odor and wastewater odor are in the range of 3.8-15.4 and 4.2-15.6 odor unit (OU)/m3 respectively. The study demonstrated that the improvements are critical in achieving reliable odor intensity measurement. This can lead to the setup of quantitative odor impact criteria for different industries and sites.

EFFECT OF 1‐METHYLCYCLOPROPENE ON AROMA COMPOUNDS IN “BIG TOP” NECTARINES AFTER SHELF LIFE

ABSTRACT “Big Top” nectarines picked at two dates (Pick 1 and Pick 2) and treated at harvest with 0 (control), 0.25, 0.5 and 1.0 µL/L 1‐methylcyclopropene (1‐MCP) when fruit ripening had already started were kept at 20 C until control fruit softened. Ethylene production was lowered by 0.25 and 1.0 µL/L doses in Pick 1 fruits and by all the doses in Pick 2 fruits. Fruit softening was delayed, but at the end of shelf life, treated fruits were as soft as the controls. Total volatile production was lowered by 0.25 and 1.0 µL/L doses in Pick 2 fruits. 1‐MCP influenced the aroma composition at the end of shelf life, yet it was not always dose dependent. Consequently, 1‐MCP changed fruit odor pattern by influencing the distribution of lactone odor units, the major odor contributors, reducing the “overmature” note and enhancing the “fresh” note.

Odour episodes in the vicinity of livestock buildings: A qualitative comparison of odour complaint statistics with model calculations

In this paper we compare odour complaint statistics of various sites in Europe, South Africa and North America with calculated odour sensation at a site in Austria, which can be used as a typical example of a well-ventilated area with prevailing west wind and a superimposed weak influence of a mountain wind system. A major goal of this work is the discussion of the general time pattern of complaint statistics and the discrepancy with the occurrence of odour sensation calculated by a dispersion model. The Austrian odour dispersion model (AODM) is a Gaussian model suitable for the prediction of ambient odour concentrations. Based on cumulative frequency distributions of calculated odour concentrations at receptor points, separation distances are obtained defined by odour impact criteria chosen as a combination of odour threshold and probability of threshold exceedance. At these separation distances, depending on the wind direction, the occurrence of odour sensation is analysed and compared with the well-known time pattern of the complaint statistics for odour. Here, the AODM is used to calculate separation distances for an odour threshold of 1 odour unit (OU) per cubic metre exceeded in 3% of the year. At a site in the Austrian North-alpine foreland, direction-dependent separation distances for a 1000 head pig unit (calculated on the basis of a 2-year time series of meteorological data) lie between 99 m for northerly winds and 362 m for westerly winds. For these direction-dependent separation distances we analysed when odour sensation can be expected in relation to meteorological parameters as well time of the day and year. For the main wind directions, West and East and odour sensation can be expected more often for higher wind velocities and a neutrally or stably stratified atmosphere around sunset. North and South winds show the typical diurnal variation of a local valley wind system with predominantly northerly daytime up-valley and southerly night-time down-valley winds. Odour sensation is therefore most likely around noon for North wind and during night-time for South wind. This time pattern of the calculated odour sensation does not fit to the time pattern of the complaint statistics, which shows complaints to occur predominantly in the afternoon and evening hours of the warm season when residents are outside. The presented comparison of odour complaint statistics with the calculated odour episodes is a helpful tool to find out when odour is perceived as most annoying. As a result, the evaluation of these values by the odour impact criteria should not only be based on statistical limits as it is done today but also by considering the annoying potential of odour due to the behaviour of the neighbours. Therefore the odour episode should be weighted by the time of the day and time of the year, as it is done with the limit values for noise.

A COMPARISON OF ODOUR COMPLAINT STATISTICS WITH MODEL CALCULATIONS OF ODOUR EPISODES

The Austrian odour dispersion model (AODM) is a Gaussian model suitable for the prediction of ambient odour concentrations. Based on cumulative frequency distributions of calculated odour concentrations at receptor points, separation distances are obtained defined by odour impact criteria chosen as a combination of odour threshold and probability of threshold exceedance. At these separation distances, depending on the wind direction, the occurrence of odour sensation is analysed and compared with the well-known time pattern of the complaint statistics for odour. Here, the AODM is used to calculate separation distances for an odour threshold of 1 odour unit (OU) per cubic metre exceeded in 3% of the year. At a site in the Austrian North-alpine foreland, direction-dependent separation distances for a 1000 head pig unit (calculated on the basis of a two-year time series of meteorological data) lie between 99 m for northerly winds and 362 m for westerly winds. For these directiondependent separation distances we analysed when odour sensation can be expected in relation to meteorological parameters as well time of the day and year. For the main wind directions, West and East, odour sensation can be expected more often for higher wind velocities and a neutrally or stably stratified atmosphere around sunset. North and South winds show the typical diurnal variation of a local valley wind system with predominantly northerly daytime up-valley and southerly night-time down-valley winds. Odour sensation is therefore most likely around noon for North wind and during night time for South wind. This time pattern of the calculated odour sensation doesn't fit to the time pattern of the complaint statistics which shows complaints to occur predominantly in the afternoon and evening hours of the warm season when residents are outside. The presented comparison of odour complaint statistics with the calculated odour episodes is a helpful tool to find out when odour is perceived as most annoying. As a result, the evaluation of these values by the odour impact criteria should not only be based on statistical limits as it is done today but also by considering the annoying potential of odour due to the behaviour of the neighbours. Therefore the odour episode should be weighted by the time of the day and time of the year, as is done with the limit values for noise.

Aroma Impact Compounds in Three Citrus Oils: Cross‐matching Test and Correspondence Analysis Approach

ABSTRACT Twenty‐three odor chemicals from 3 Citrus essential oils (lemon, Valencia orange, and Citrus sudachi) were selected as the potent character‐impact compounds on the basis of their limited odor unit values, and then every chemical was cross‐matched by sensory test to the 3 oils to attribute each aroma character to 1 of the 3 Citrus oils. The matching‐frequency data (ratio data) obtained was subjected to correspondence analysis and graphed on a diagram. Consequently, it was found that the aroma character of lemon oil was mainly represented by citral, with a high matching frequency of 0.89 (59 counts out of 66 trials, x2o= 93.36). The orange character consisted mostly of linalool and nonanal. α, β‐Pinene, α‐sinensal and myrcene were related to the aroma of C. sudachi oil. The application of the cross‐matching test and correspondence analysis in the characterization of food aromas has never been reported in the literature to date, and the validity of these methods was successfully demonstrated by our study.

Evaluation of Four Farm-scale Systems for the Treatment of Liquid Pig Manure

In some regions in the Netherlands, high pig concentrations and limited availability of arable land have led to a surplus of manure which results in high off-farm manure disposal costs. The aim of manure treatment is to lower manure transport costs by reducing the volume and to improve market prospects by changing the nutrient composition. The objective of this study was to promote the introduction of manure treatment in the Netherlands by giving research support to farmer initiatives and providing them with data on the actual performance of their system with regard to product composition, mass flows, gaseous emissions, and economic feasibility. Four farm-scale systems for treatment of liquid pig manure were studied: two systems for mechanical separation, one for nitrification/denitrification, and one for evaporation. The results showed that a wide range of manure products could be obtained that differ in dry matter, N, P, and K content. The emission of ammonia and odour varied from 1·8 to 55 g t −1 [manure] and from 3·8×10 3 to 1·3×10 7 [European odour units] t −1 [manure], respectively. The nitrification/denitrification showed the highest emission of greenhouse gases (48 kg [carbon dioxide equivalents] t −1 [manure]), mainly nitrous oxide (N 2 O), whereas the emission of the other systems was 12–17 kg [CO 2 -eq.] t −1 [manure]. The critical success factor for the operation of the manure treatment installations turned out to be not of technical but of economical nature. The manure treatment costs, including variable and fixed cost, varied from 7 to 17 € t −1 (excluding value added tax). To be cost effective in comparison with the disposal of untreated manure, these costs must be balanced out by the sale or the lower disposal costs of the manure products. As market prospects and disposal costs for manure and its products differ from case to case, no generally preferred manure treatment technique can be pointed out from this study, as local market circumstances must be taken into account.

Dispersion of odorous gases in the atmosphere — Part I: Modeling approaches to the phenomenon

The study of odor dispersion, particularly its modeling, is an important decision tool for estimating the impact of human activities on the environment and its populations. In this sense, software to model the dispersion of odorous gases was developed and is presented. It is based on the theory established by Högström on the odor dispersion of puff emissions. This theory is applied to Gaussian models and takes the frequency of values for odor intensity over any time period into account. Such a model is able to consider the instantaneous characteristics of odor perception by human beings. Nine approaches that explore several solutions within the Gaussian domain for the atmospheric dispersion problem are proposed in software named ODODIS (ODOr DISpersion Software). This software was developed to test the different solutions. Four of these solutions are based on the punctual (or point source) emission or classic equation; two are based on the instantaneous punctual emission equation; and the other three, on the prolonged punctual emission equation (puff models). Measuring units used for the input data may be g s − 1 or OU (Odor Units). The software developed here satisfies the need to obtain instantaneous data of either a passive or an odorous gas at a specific point of an area. The simulation time varies depending on the purpose of the analysis. Mean concentration values may be obtained by integrating the instantaneous results generated by the model.

Occupational hygiene in a Finnish drum composting plant

Bioaerosols (microbes, dust and endotoxins) and volatile organic compounds (VOCs) were determined in the working air of a drum composting plant treating source-separated catering waste. Different composting activities at the Oulu drum composting plant take place in their own units separated by modular design and constructions. Important implication of this is that the control room is a relatively clean working environment and the risk of exposure to harmful factors is low. However, the number of viable airborne microbes was high both in the biowaste receiving hall and in the drum composting hall. The concentration (geometric average) of total microbes was 21.8 million pcs/m 3 in the biowaste receiving hall, 13.9 million pcs/m 3 in the drum composting hall, and just 1.4 million pcs/m 3 in the control room. Endotoxin concentrations were high in the biowaste receiving hall and in the drum composting hall. The average (arithmetic) endotoxin concentration was over the threshold value of 200 EU/m 3 in both measurement locations. In all working areas, the average (arithmetic) dust concentrations were in a low range of 0.6–0.7 mg/m 3, being below the Finnish threshold value of 5 mg/m 3. In the receiving hall and drum composting hall, the concentrations of airborne microbes and endotoxins may rise to levels hazardous to health during prolonged exposure. It is advisable to use a respirator mask (class P3) in these areas. Detected volatile organic compounds were typical compounds of composting plants: carboxylic acids and their esters, alcohols, ketones, aldehydes, and terpenes. Concentrations of VOCs were much lower than the Finnish threshold limit values (Finnish TLVs), many of the quantified compounds exceeded their threshold odour concentrations (TOCs). Primary health effects due VOCs were not presumable at these concentrations but unpleasant odours may cause secondary symptoms such as nausea and hypersensitivity reactions. This situation is typical of composting plants where the workers are exposed to dozens of VOCs simultaneously. The odour units (OU/m 3) were measured using olfactometer. The numbers were 23,000 OU/m 3 at the output end of the composting drum and 6300 OU/m 3 in the exhaust pipe. Inside the composting hall, the number of odour units was 500 and 560 OU/m 3.

산업단지에서 배출되는 악취원인물질의 규명

As a typical example of simultaneous analysis of the odorous compounds, the volatile organic compounds from inventory sources in Seongseo industrial area were concentrated and analyzed with thermal desorber/GC/MSD, and major malodorous compounds were estimated. Odor intensity and odor concentration was analyzed simultaneously During a period from November in 2002 to December in 2003, this study was conducted to evaluate malodor emission characterization in major treatment facilities. The major components were Dimethyl sulfide, Dimethyl disulfide, Methyl mercaptane, Ammonia, Benzene, Toluene, m,p-xylene, o-xylene, Styrene, 1,2,4­T.M.B and 1,3,5-T.M.B. Among the six major inventory sources, the odor unit concentration of Night-soil disposal facilities was the highest,

New methods for fast on-site measurement of odorous compounds

New methods for measurement of odorous gases, especially for aerosol-bound chemical compounds, have been developed in the Department of Measurement Technology (Technical University of Hamburg Harburg – MT-TUHH). Odorous compounds in the waste gases produced by the food industry were analysed based on high-volume aerosol sampling techniques, enrichment on solid phase micro extraction (SPE) cartridges and analytical measurement techniques using thermal desorption gas chromatography–mass spectrometry. The analysis results were compared to classic analytical procedures using adsorbence materials (Tenax) for enrichment. In comparison to aerosol sampling, analysis of Tenax samples was found to be ineffective, especially for analyzing polar semi volatile compounds. In addition, sensor arrays were also used in the study to characterize odors of different waste gases emitted by food production facilities. Measuring the odor units of the waste gas of a fat producing factory, the results of sensor-array-measurements show good correlation with results obtained with olfactometric measurements.

A new method for measuring emission of odour from a rendering plant using the Danish Odour Sensor System (DOSS) artificial nose

This paper presents Danish experiences with measurement of odour from a rendering plants bio-filter by use of a recently developed Danish Odour Sensor System (DOSS). A rendering plant produces numerous odorous compounds and might cause annoyance in the environment. The plant management wants to minimize the amount of odour components released into the surroundings. The intention of the DOSS project is to develop a so-called electronic nose with a fast response time for use as an on-line odour-monitoring tool in the exhaust from bio-filters. The main DOSS objective is to develop and evaluate gas sensors and sensor systems (collectively called electronic noses) for industrial applications, specifically a system for on-line process control. The sensors should provide real-time measurement assessment of odours at the source and possibly at the receptor location. Bio-filter outlet is estimated to be less than 5000 OU/m 3 (Odour Units). The DOSS uses six QMB sensors, six MOS sensors and four chemical/infrared/capacitive sensors for measuring O 2, H 2O, CO, CO 2. The data during instrument development is gathered from sample bags and compared with reference odour concentrations (OU/m 3). Results from experiments are presented. Principal components analysis (PCA) and partial least squares (PLS) regression plots indicate good classification and prediction expectation. Preliminary results on interfering compounds, e.g. H 2O, H 2S and CO 2 are shown. The method was thus far developed and evaluated under laboratory conditions. Generally, the results obtained with the electronic nose measurement method showed a good repeatability and a potential to get useful results comparable with odour emission over the range 1000–30,000 OU/m 3. Experiments with the DOSS have shown that the method has a high potential as fast, reliable odour-monitoring tool for rendering plant emission monitoring.

The Impact of Supplemental Dietary Methionine Sources on Volatile Compound Concentrations in Broiler Excreta

The impact of different Met sources on broiler fecal odor volatiles was determined by evaluating the types of sulfur compounds produced in broiler excreta. Two experiments were conducted using straight-run broiler chicks randomly distributed in battery cages, with 3 replicate pens of 16 birds each. The treatment groups were 1) dry Met hydroxy analogue (dry MetHA), 2) sodium methioninate aqueous solution (NaMet), 3) liquid Met hydroxy analogue (Liq MetHA), 4) D,L- Met, and 5) no supplemental Met (control group). The Met activities of each Met source were 52, 45.9, 88, and 98%, respectively. All diets were formulated to contain either 0.8% (experiment 1) total Met activity or 0.5% Met activity in the starter and 0.38% Met activity in the grower (experiment 2) (except the control group, 0.35% Met activity), but otherwise met NRC nutrient requirements (NRC, 1994). Diets were fed ad libitum from d 1 to 6 wk of age. There were no significant differences in BW among the treatments. All excreta were collected in litter pans lined with aluminum foil. In experiment 1, at wk 6, broiler excreta were collected for a 24-h period, and 4.5 g of broiler excreta from each treatment group was collected into 15-mL headspace vials. Samples were analyzed by gas chromatography/mass spectrometry (GC/MS). The volatile sulfur compounds that were identified and quantified in the broiler excreta were H2 S, carbonyl sulfide (COS), methyl mercaptan (CH3 SH), dimethyl disulfide (CH3 SSCH3), and dimethyl trisulfide (CH3 SSSCH3). The NaMet treatment group had significantly higher concentrations of H2 S, COS, and CH3 SSCH3 compared with all other treatment groups. The Liq MetHA group had significantly lower concentrations of H2 S, COS, CH3 SH, and CH3 SSCH3 compared with the other treatment groups. The dry MetHA group significantly had the highest concentration of CH4 SH. The D,L-Met treatment group had the significantly highest concentration of CH3 SSSCH3 and the lowest concentration of H2 S. The control group had the significantly lowest concentrations of CH3 SH, CH3 SSCH3, and CH3 SSSCH3 compared with the other treatment groups. In experiment 2, at wk 6, an electronic nose was used to evaluate 15 air samples per treatment group. In addition, 15 air samples (containing 6 to 8 L of air in a Tedlar bag, 3 samples per treatment group) were collected for odor evaluation by a sensory panel. Electronic nose sensor data revealed that volatile compounds in broiler excreta from the control group were significantly different from the other 4 treatment groups. Evaluation of the air samples by a sensory panel determined that there was a statistically significant difference in odor threshold detection between the control group and the other treatment groups. The dilutions to threshold of control group, NaMet, dry MetHA, Liq MetHA, and D,L-Met were 350, 492, 568, 496, and 526 odor units, respectively. These findings demonstrate that dietary Met sources significantly influenced odorous volatile concentrations in broiler excreta.

The odour of digested sewage sludge - determination and its abatement by air stripping

This paper describes a project to investigate the odour of sewage sludge after anaerobic digestion. The impact of air stripping on the odour of liquid sludge and on the quality of the dewatered product was evaluated at a full-scale sludge treatment installation. A continuous and a batch air-stripping mode were tested. Odour samples were collected during air stripping from the liquid sludge and from the biosolids surface during long term storage. The biosolids were also analysed for hedonic tone and for their potential odour expressed as an odour unit per unit mass. The odour emission profiles for continuous and batch air stripping demonstrated a reduction in the overall (time weighted) emissions during a 24 hr-period compared with emissions from the quiescent liquid storage tank. The averaged specific odour emission rate (Esp) of the biosolids derived from the continuous process was only 13% of the Esp of the biosolids derived from unaerated liquid sludge during the first month of storage. The results of the total potential odour and the hedonic tone of the biosolids underpin the beneficial effects of the air stripping. Odour dispersion modelling showed a noticeable reduction in overall odour impact from the sludge centre when air stripping was applied. The reduction was primarily associated with the reduced odour from stockpiled biosolids. The continuous air-stripping mode appeared to provide the greatest benefits in terms of odour impact from site operations.

清酒の熟成によるソトロンおよびフルフラールの変化

The contribution of sotolon and furfural to the aroma of aged sake was investigated. These compounds were strongly detected in aged sake by GC-olfactometry. They were quantified by solvent extraction and GC-MS analysis. The coefficient of variation of sotolon decreased to less than 10% by using 13 C2-labeled sotolon instead of 3-octanol as an internal standard. Concentration of sotolon in aged sake was higher than its recognition threshold but furfural was not. The odor unit of sotolon in 26 years old sake was 61. It was suggested that sotolon contributes greatly to the aroma of aged sake. Concentrations of α-ketobutyric acid and acetaldehyde, which are considered to be precursors of sotolon, were investigated and a correlation with sotolon was observed. However, the possibility of another mechanism of sotolon formation was also suggested.

Volatile constituents of Malay rose apple [Syzygium malaccense (L.) Merr. &amp; Perry

AbstractThe volatile constituents of Malay rose apple fruits [Syzygium malaccense (L.) Merr. &amp; Perry] growing in Cuba were analysed by GC–MS and GC; 133 compounds were identified in the aroma concentrate, of which 2‐phenylethanol and its esters (2‐phenylethyl acetate, 2‐phenylethyl isopentanoate, 2‐phenylethyl benzoate and 2‐phenylethyl phenylacetate) were found to be the major constituents. By correlating odour thresholds with the concentrations of volatiles (odour unit values), the relative contribution of individual compounds in fruit aroma was assessed. The exotic aroma character of Malay rose apple is the interaction of rose (2‐phenylethanol and its esters) and herbaceous (1‐octen‐3‐ol) notes contributing to the complexity of the aroma. Copyright © 2003 John Wiley &amp; Sons, Ltd.

Odor and gas release from anaerobic treatment lagoons for swine manure.

Odor and gas release from anaerobic lagoons for treating swine waste affect air quality in neighboring communities but rates of release are not well documented. A buoyant convective flux chamber (BCFC) was used to determine the effect of lagoon loading rate on measured odor and gas releases from two primary lagoons at a simulated wind speed of 1.0 m s(-1). Concentrations of ammonia (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), sulfur dioxide (SO2), and nitric oxide (NO) in 50-L air samples were measured. A panel of human subjects, whose sensitivity was verified with a certified reference odorant, evaluated odor concentration, intensity, and hedonic tone. Geometric mean odor concentrations of BCFC inlet and outlet samples and of downwind berm samples were 168 +/- 44 (mean +/- 95% confidence interval), 262 +/- 60, and 114 +/- 38 OU(E) m(-3) (OU(E), European odor unit, equivalent to 123 microg n-butanol), respectively. The overall geometric mean odor release was 2.3 +/- 1.5 OU(E) s(-1) m(-2) (1.5 +/- 0.9 OU s(-1) m(-2)). The live mass specific geometric mean odor release was 13.5 OU(E) s(-1) AU(-1) (animal unit = 500 kg live body mass). Overall mean NH3, H2S, CO2 and SO2 releases were 101 +/- 24, 5.7 +/- 2.0, 852 +/- 307, and 0.5 +/- 0.4 microg s(-1) m(-2), respectively. Nitric oxide was not detected. Odor concentrations were directly proportional to H2S and CO2 concentrations and odor intensity, and inversely proportional to hedonic tone and SO2 concentration (P < 0.05). Releases of NH3, H2S, and CO2 were directly proportional (P < 0.05) to volatile solids loading rate (VSLR).

Odor and Gas Release from Anaerobic Treatment Lagoons for Swine Manure

Odor and gas release from anaerobic lagoons for treating swine waste affect air quality in neighboring communities but rates of release are not well documented. A buoyant convective flux chamber (BCFC) was used to determine the effect of lagoon loading rate on measured odor and gas releases from two primary lagoons at a simulated wind speed of 1.0 m s−1 Concentrations of ammonia (NH3), hydrogen sulfide (H2S), carbon dioxide (CO2), sulfur dioxide (SO2), and nitric oxide (NO) in 50-L air samples were measured. A panel of human subjects, whose sensitivity was verified with a certified reference odorant, evaluated odor concentration, intensity, and hedonic tone. Geometric mean odor concentrations of BCFC inlet and outlet samples and of downwind berm samples were 168 ± 44 (mean ± 95% confidence interval), 262 ± 60, and 114 ± 38 OUE m−3 (OUE, European odor unit, equivalent to 123 μg n-butanol), respectively. The overall geometric mean odor release was 2.3 ± 1.5 OUE s−1 m−2 (1.5 ± 0.9 OU s−1 m−2). The live mass specific geometric mean odor release was 13.5 OUE s−1 AU−1 (animal unit = 500 kg live body mass). Overall mean NH3, H2S, CO2 and SO2 releases were 101 ± 24, 5.7 ± 2.0, 852 ± 307, and 0.5 ± 0.4 μg s−1 m−2, respectively. Nitric oxide was not detected. Odor concentrations were directly proportional to H2S and CO2 concentrations and odor intensity, and inversely proportional to hedonic tone and SO2 concentration (P < 0.05). Releases of NH3, H2S, and CO2 were directly proportional (P < 0.05) to volatile solids loading rate (VSLR).