In this study, the removal characteristics of reduced sulfur compounds (RSC) were investigated against activated carbon (AC) by means of electric cooling and thermal desorption. To this end, three types of AC materials were selected and tested against gaseous RSC standards prepared at 50 ppb concentration. Each of these AC materials designated with its own target odorant compounds was tested for the removal rate of RSC by comparing their quantities between prior to and after passing the adsorption tube. All the analysis of RSC was made by Gas Chromatography (GC)/Pulsed Flame Photometric Detector (PFPD) combined with Air Server (AS)/Thermal Desorber (TD). The rate of RSC removal was quantified as a function of RSC loading time (Exp. 1) and of RSC flow rate into TD (Exp. 2). The results of Exp. 1 showed that the adsorption of RSC increased with RSC loading time (from as little as 1 to 20 min). In Exp. 2, the adsorption of RSC also increased in relation to RSC flow rate (10 to 100 mL/min). The removal rate of RSC was also distinguished by chemical properties such as the compounds of low molecular weights (H₂S and CH₃SH) vs. high ones (DMS and DMDS).

In this study, microbial investigation is accomplished for 554 Jeot-kal samples (102 of Jeot-kal, 448 of Seasoned Jeot-kal and 4 of Sik-khe, respectively) that corresponds with Coliform-bacteria, Escherichia coli, Aerobic live bacteria as hygienic indicator microorganisms, and Staphylococcus aureus, Vibrio parahaemolyticus as Food-borne pathogenic microorganisms. Based on the methods in Korea Food Code, reliable data are obtained as follows; in 31.9% rate of the samples, Coliform bacteria are verified in the extent of 0~20,000 CFU/g as 2.3 logCFU/g. Especially, Seasoned Jeot-kal (37.7%, 2.3 logCFU/g) are detected to 6 and 2 folds higher than those of Jeot-kal, 5.9% and 1.4 logCFU/g. Likewise, Escherichia coli is detected from 9 samples only in Seasoned Jeot-kal, that includes seasoned squid, seasoned octopus, seasoned roe of pollack, seasoned large-eyed herring and seasoned hairtail. Aerobic live bacteria are also detected in the range of 0~8.9 × 108 CFU/g. Against salinity, E. coli are detected in samples only less than 10% salinity. Concomitantly, aerobic live bacteria count is decreased to 5.5~3.6 log CFU/g upon the salinity is increased up to 25%. However, S. aureus and V. parahaemolyticus are not detected in 554 samples, presumptively referring Jeot-kal products are somehow free from such food-borne pathogens. As the results above, we deliberately consider that the sanitary control in Jeot-kal, which be necessarily fermented- as well as non-microbially inactivated should be ensured in near future and also suggest an effectual microbial standard corresponding to the Negativity in E. coli for Jeot-kal products.

To analyze trace-level, reduced sulfur compounds (RSC) in ambient air, gas chromatography (GC) is used as the commonest method. The GC-based analysis is generally conducted by transferring samples via direct injection into GC or by the combined treatment of cryofocusing (CF) and thermal desorption (TD). In this study, experimental bias involved in GC analysis is examined by evaluating the calibration properties of each transfer approach. To this end, the detection properties of RSCs were evaluated with respect to the two major variables of sample concentration and sample volume. The recovery rate of TD application was also discussed based on the most recent findings in which its recovery rate is compared against the results derived by the direct injection method. The overall results suggest that the TD-based analysis of RSCs can be optimized by unifying the experimental conditions between sample and standard gases.

In this study, the performance of fast gas chromatography system was evaluated using VOC standards prepared in both liquid and gaseous phase. When the liquid‐phase VOC standards were analyzed by both direct injection and HS‐SPME method, all the chromatographic separation was completed within 4 minutes. The calibration experiments were conducted further using gaseous standard of BTX. The calibration results derived by direct injection method generally showed good linearities, regardless of phases, while it was not the case for HS‐SPME method. In case of liquid‐phase standard, MDL values for direct injection and HSSPME method were calculated in the range of 0.07~0.19 to 0.63~3.76 ng, respectively. In contrast, MDL values for gaseous standard were 0.27~0.45 and 1.94~6.90, respectively. The reproducibility of our method, when expressed in terms RSE, showed above 5 %. When the sensitivity of different techniques is compared, the calibration slope values of BTX decreased on the order: direct injection of liquid‐phase standard > HSSPME method of liquid‐phase standard > direct injection of gaseous standard > HS‐SPME method of gaseous standard. Although fast GC is very efficient to reduce the total running time significantly, extended studies are desirable to improve its reproducibility.

In this study, the concentrations of various hydrocarbon (HC) were measured from the ambient air at Mallipo beach after the Hebei Spirit oil spill accident on Dec. 2007. To determine HC levels in those samples, the analysis was made by SPME method aided by the GC/MS system. To produce quantitative HC data, all the calibrations were conducted in reference to toluene. The HC released from oil-covered soils were also analyzed by headspace method; according to this analysis, the concentrations of paraffinic (9), aromatic (8) and miscellaneous components (5 compounds) were found above a few tens of ppb. In ambient samples, 10 compounds were measured which consisted of 8 paraffinics and 2 aromatics. And they have the maximum and minimum concentration that were 34.3 ppb (n-undecane) and 2.84 ppb (toluene). However, the concentration levels of the 2 aromatic compounds (toluene and xylene) measured during this study period were not distinguished from those commonly observed from ambient air. Based on our analysis, we were able to confirm that the types and the concentration levels of hydrocarbons in ambient samples were in accord with those derivable from a large oil spill accident and the resulting weathering processes.

The purpose of this study is to assess the cause of offensive odor incident that took place at Shin-Gil district in Seoul on 17. Nov. 2007. Air samples were collected from both the inside and outside of the accidental sewage site both at the right after and long after the accident and analyzed by GC/MS method. The results of our initial analysis showed that there were 39 compounds with sufficiently detectable quantities (e. g., above ~ 1 ppb). These compounds can be classified into 3 classes of chemical groups which include: Benzene, Indene, and Miscellaneous. It further indicated that compounds with benzene(C₆H₆) ring were the most abundant species followed by several compounds with indene(C₉H₈) structure. Based on our analysis, we conclude that the release of industrial solvents with indene resin contributed most significantly to the observed malodor incident.

In this study, the spatial and temporal distribution of odorants in ambient air was investigated at three measurement points in a University campus in Seoul city during a 15 day study period. The concentrations of 12 target analytes designated as malodor compounds by KMOE were measured through time. The highest mean concentration (in ppb unit) was found from NH₃(25.3) followed by styrene (0.51) ＞ acetaldehyde (0.13) ＞ H₂S, propionaldehyde (0.07) ＞ butyraldehyde, isovaleraldehyde, and valeraldehyde (0.06) ＞ DMDS (0.04) ＞ TMA (0.03) ＞ CH₃SH and DMS (0.01). Comparison of odorant data showed fairly strong distinctions across diurnal period, while differences in concentration levels were not clear enough between different sampling locations. The results of correlation analysis showed that the concentrations of DMS and NH₃ were strongly correlated with relative humidity. In addition, most of reduced sulfur compounds (RSC) exhibited strong correlations with each other. When the odorant concentrations were converted into odor intensity, the values were typically found below the odor degree of 1. The odor intensity, if assessed by the maximum values of each compound, were generally in between 1~2 odor degree level (e.g., H₂S, CH₃SH, DMDS, acetaldehyde, and TMA). The results of this study thus show that most odorant species occurred below the threshold value at clean space like a University campus. Hence, more efforts are desirable toward the development of the analytical technique at various concentration levels.

In order to accurately analyze trace-level, reduced sulfur compounds (RSC) in ambient air, one needs to rely on the thermal desorption technique (TD) to atone for the limited sensitivity of direct gas chromatography (GC) analysis. In this study, the relative performance of GC/PFPD system combined with TD unit was evaluated to help accurately determine RSC based on the comparative analysis of two types of calibration approaches. Hence, calibration results of RSCs were compared by controlling sample transfer system (air server (AS) and TD unit) between the two contrasting calibration approaches such as: incremental-loading of a given standard with the fixed standard concentration (FSC) vs. supply of standards made at multiple concentration points at the fixed standard volume (FSV). The results of our study indicate that RSC calibration is affected fairly sensitively by sample loading conditions of the AS/TD system. It is hence necessary to delicately control the TD operation conditions for the accurate quantification of RSCs, when GC/PFPD system with TD is employed for RSC analysis.

In this study, odorous emissions from decaying foods were investigated with respect to trimethylamine and ammonia. To this end, three food types (egg, mackerel, and cuttlefish) were used for decaying experiments in which food samples were preserved in throwaway syringes (weight for each sample of 5 g). All decaying experiments advanced for one month under the normal temperature and ventilation. The average concentrations of TMA from egg, mackerel, and cuttlefish samples were measured as 0.6, 5.8 and 130 ppm, respectively, while those of NH₃ as 554, 385, and 531 ppm, respectively. According to our experiments, the concentrations of TMA and NH₃ increased with the progress of corruption. The release of malodor compounds tend to vary sensitively with the changes in temperature and humidity. In case of TMA, a strong correlation with temperature was observed on the order: mackerel ＞ egg ＞ cuttlefish. However, in the case of NH₃, strong correlations were seen to exist with humidity. Changes of TMA concentration were accompanied by changes of pH, especially from mackerel and cuttlefish. NH₃ also showed a similar trend of pH change from samples. When the results of TMA measurements were evaluated in terms of odor intensity, egg, mackerel, and cuttlefish are recorded as 4.36, 5.25 and 6.46, respectively. Likewise, odor intensity of NH₃ measurements was found as 6.96, 6.7 and 6.93, respectively. The results of our odor study suggest that a unique pattern of odor release is developed from decaying food samples.

To resolve coelution phenomenon of acetone and acrolein in the HPLC‐based analysis of carbonyls, we attempted to find the optimal conditions for their separation. For the purpose of this study, the collection of carbonyl Compounds is made by DNPH‐coated cartridges. Quantification of carbonyls is then initiated by the formation of hydrazone derivatives that are then separated by HPLC and detected by UV‐VIS spectroscopic detector (at 360 nm). To the course of this experiment, we examined the influences of the three major experimental variables such as 5 temperature (25, 30, 40, 50 and 60℃), 2 flow rate (1.0 and 1.2 mL min‐1), and variable relative composition of mobile phase (among acetonitrile, water, and tetrahydrofuran). According to our experiments, the optimal condition for separation was found at flow rate of 1.2 mL min‐1 and temperature of 32℃ with the mobile phase composition of acetonitrile:water:tetrahydrofuran = 34 : 52.8 : 13.2.

In this study, we attempted to evaluate the relationship between air dilution sensory test and instrumental detection method for samples containing various odorous compounds. For the purpose of our comparative study, the analysis of malodor compounds was made using a total of 70 samples collected from three industrial sectors which include: Food & beverage, Waste treatment and cleaning, and Miscellaneous facilities. The results of instrumental analyses converted into three different odor indices (the odor concentration (OC), odor quotient (OQ), and odor intensity (OI)) were used to statistically sort out individual odorous components with the major impact. The results of multiple regression analysis between air dilution ratio value and instrumental odor concentration (of individual 12 compounds) indicate that butyraldehyde, CH₃SH, NH₃, and H₂S are the major odorous compounds that contribute most significantly to odor strength for the sample types investigated in this study.

In order to validate the meteorological and odor dispersion modeling methods, the measured meteorological parameters such as wind speed and direction and odor intensities were compared with those calculated from the models. The CALMET and CALPUFF models which were recommended by USEPA were used to predict the meteorological variable and odor concentrations. The average time of odor concentration was 10 mins. to consider instantaneous response nature of the odors. The results showed that model predictions were in good agreement with the measurements. It is expected that the modeling method presented in this paper will be useful to assess the impact of odors from industrial complex to near-by residential areas.

The emission concentrations of VOC and various odorous compounds were measured from different indoor process units located in 19 companies at the Ban Wall industrial complex from Jun. 2004 to Jan. 2005. The purpose of this study was to investigate the indoor pollution levels of various industrial facilities with respect to bothmalodorous compounds and volatile organic compounds (VOC). We also intended to build the database under the conditions affected by various anthropogenic processes with an aid of a statistical treatment. The three samplingmethods and five analytical techniques were applied tomeasure the sum of up to 32 individual compounds. According to this study, we were able to identify the importance ofmajormalodor compounds which include carbonyl compounds, reduced sulfur compounds, ammonia and trimethylamine. On the other hand, relative contribution of VOC as sources ofmalodor was ofminor significance except such compound as toluene. The overall results of this study thus indicate that the concentration levels of VOC in themanufacturing facilities are high enough to affect indoor laboring conditions.

In this study, an attempt was made to measure uncertainties involved in the analysis of gaseous VOC standards prepared at various dilution stage. A GC/FlD system equipped with air server/thermal desorption (AS/TD) unit was used to draw calibration curves for the known amounts of VOC gases (including benzene, toluene, xylene, and styrene) prepared at four individual concentrations (10, 20, 50, and 100 ppb). The calibration curves obtained from standards of each respective concentration were compared with each other. It was found that the loss of samples was more prominent with decreasing standard concentrations (e.g., one prepared at 10 ppb) and that the heaviest compound, styrene exhibited the most noticeable loss than the others. In this study, an ancillary experiment was also conducted to evaluate the compatibility of standards between gaseous (using Tedlar bag) and liquid phases (using tube method). Based on this comparative analysis, the compatibility between two standard type was evaluated in terms of the recovery ratio between gas and liquid: 56 (benzene), 42 (toluene), 31 (p-xylene), and 25% (styrene).

본 연구에서는 악취민원이 빈발한 경기도 안산시에 위치한 반월공단의 주거지역과 공단지역 등을 중심으로 주요 관리대상으로 설정된 악취성분들에 대한 환경대기 중 농도분포 특성을 2년여 기간동안 6차례에 걸쳐 조사하였다. 이들의 거동을 이해하기 위해, 시간적(오전과 오후) 및 공간적(공단 내외부의 위치) 기준으로 분포특성에 대한 비교를 시도하였다. 그 결과, 오전시간대에 비해 오후시간대에 고농도 분포가 현저하게 높은 것으로 나타났다. 이와 유사하게 공간적인 기준으로 비교한 결과도 공단 내부에서 관측한 결과에서 대부분의 성분들이 고농도를 유지하는 것을 확인할 수 있었다. 본 연구의 결과는 안산시 주변 및 공단지역의 환경대기 중에 존재하는 악취성분들이 시간적 및 공간적 기준으로 다양한 분포특성을 취한다는 것을 보여주었다.

Odor emission characteristics of unit processes in 10 livestock farms and 3 manure treatment facilities in Kyonggi province were examined in terms of odorous compound concentration and dilution ratio values of the threshold limit measured by instrumental analysis and air dilution sensory test, respectively. The highest odor concentration was detected at the compositing process unit of each facility and the dilution ratio showed high correlation with the treatment capacity as well as hygiene of the facility. Odor intensities in some facilities showed severe fluctuations (10 to 27 times difference) in response to the wind speed and direction as well as other weather conditions. According to the instrumental analysis, the major odorous compounds in the research area appeared to be ammonia, hydrogen sulfide, trimethyl amine, acetaldehyde and carbonyl compounds. Although some facilities breed same livestock, the types of odorous compounds as well as their concentration profiles were dependent on the type of composting process and management skill. In addition, dilution ratio of the threshold limit did not always show positive correlation with the odorous compound concentrations, which indicates the necessity of applying both methodologies, sensory test, and instrumental analysis.