The principal hygienic problem caused by livestock industry is the odor exposed to farm workers. This study was performed to assess air cleaner efficiency for reducing odor through on-site evaluation. The concentration of ammonia and hydrogen sulfide, which are major odorous compounds generated from livestock building, were monitored by realtime direct recorder. The odor mixture was measured by air dilution method applying human noses of five panels. Their reduction efficiencies were represented by difference between initial concentration exhausted by non-treatment and concentration measured after treatment of respective control mechanism (water, germicide and plasma ion) of air cleaner. Mean levels of ammonia and hydrogen sulfide were 1.84 (SD:0.22) ppm and 76.83 (SD:1.37) ppb for non-treatment, 1.23 (SD:0.09) ppm and 59.07 (SD:2.68) ppb for wet scrubber (water), 1.08 (SD:0.03) ppm and 58.55 (SD:1.62) ppb for wet scrubber (germicide), and 0.96 (SD:0.03) ppm and 53.66 (SD:1.37) ppb for plasma ion, respectively. Mean dilution factors of odor mixture were 100 for non-treatment, 66.9 for wet scrubber (water), 144.2 for wet scrubber (germicide), and 66.94 for plasma ion, respectively. Based on the results obtained from on-site evaluation, ammonia and hydrogen sulfide showed the mean reduction efficiency of 40% and 25.7% compared with non-treatment process of air cleaner, respectively. In the case of odor mixture, the highest dilution factor was observed at wet scrubber (germicide) compared with other control mechanism of air cleaner.

This study attempts to investigate the impact of pollution by VOCs at schools located around Shihwa national industrial complex. Schools around the Shihwa national industrial complex were divided into two categories based on location, with five schools located near the industrial complex and five schools located near housing development. Samples of the indoor air and the outdoor air were collected from each classified school and analyzed to evaluate the impact of the industrial complex on each school through a comparison and to find the correlation between them. In combination with this, this study attempted to conduct comparative evaluations of the schools in which there might be relatively higher indoor air pollution since new construction and extension or remodelling had recently been carried out with other schools. The samples collected from 10 places in total were analyzed, using GC/MS. TVOCs, and individual component of VOCs, were detected in the schools near shihwa national industrial complex at higher levels than in the schools nearby housing development. TVOCs were detected at the schools in the industrial complex st levels of 166.5 μg/m3, that is, about 1.5 times higher than the level detected at the schools outside the industrial complex. TVOCs were found in the indoor air of the schools that had been extended or remodelled less than 3 years ago at levels of 188.8 μg/m3, while in schools where more than 3 years had passed since extention or remodelling they were found at levels of 97.5 μg/m3, meaning they were about 1.9 times higher in schools in the first 3 years.

The study analyzed performance assessment factors of odor sensors from 4 different manufacturers, including minimum detection limit, humidity stability and temperature stability. In the minimum detection limit assessment, only one electrochemical gas sensor was able to detect ammonia and hydrogen sulfide at the concentration of 5 ppb. The standard deviation ratio was over 10%, and it increased as humidity rose. The range of temperatures in which the electrochemical and photoionization gas sensors could function well was between 25oC and 40oC, and the sensor output values were unstable at low temperatures. Regarding the temperature stability of the metal oxide semiconductor sensor for measuring complex odors, the sensor output values dropped considerably to 0~10oC, and were similar to the concentrations of odor gases generated at 25oC. The results of the test of odor sensor outputs after temperature and humidity pre-treatment revealed that the respective stable output values at 50% humidity and 25oC were similar to the concentrations of manufactured odors. In terms of temperature and humidity stability of the NH3, H2S and Complex odor sensors, all target substances had stable output values at 25~40oC and 50~65% relative humidity, and unstable values at low temperatures and high humidity. Therefore, implementing pretreatment systems including temperature and humidity correction (25~40oC, 50~65% RH) is necessary for the stable use of odor sensors.

The metal plating industry produces a large amount of wastewater generally containing heavy metals with various chemical compounds; as such, treating the wastewater is both an environmental and an economic challenge. A vacuum evaporation system has been developed to effectively reduce the volume of plating wastewater. However, the gas stream discharged from the distillation unit of the evaporator is often contaminated with high concentrations of odorous compounds such as ammonia and dimethyl disulfide (DMDS). In this study, a non-thermal plasma process operated in wet conditions was applied to remove the odorous compounds, and it showed high removal efficiencies of greater than 99% for ammonia and 95% for DMDS. However, the gas flowrate more substantially affected the efficiency of ammonia removal than the efficiency of DMDS removal, because the higher the gas flowrate, the shorter the contact time between the odorous compound and the mist particles in the wet plasma reactor. The analyses of the maximum removal capacity indicated that the wet non-thermal plasma system was effective for treating the odorous compounds at a loading rate of less than 20 mg/m3/min even though the lowest amount of electrical power was applied. Therefore, the wet-type non-thermal plasma system is expected alleviate to effectively abate the odor problem of the vacuum evaporator used in the treatment of plating wastewater.

The correlation analysis between odor sensor and air dilution olfactometry method with odor emission facilities was performed for the real-time evaluation of odor emitted from the 13 facilities. The total correlation was less significant for all facilities due to various emission characteristics of odor. The correlation for the individual facility, however, showed a higher correlation coefficient (R=0.7371~0.9897). Especially, the strong correlation (above 0.9) was observed for the industry type with the odor characteristics like tobacco, styrofoam, acetic acid, and burning smell. The repeated odor measurements using the odor sensor showed good reproducibility with the mean relative standard deviation of 5.06%. The odor sensor could be useful tools for identifying and evaluating odor with an olfactometry in field, if the use and proofreading of the odor sensor are improved by a standardized method.

This paper is focused on an economic analysis of applied air pollutant control technologies used for the particulate matters present in subway. Beneficial effects such as reduction in medical expenses and prevention of productivity loss and death are achievable through the adaptation of control technologies. The result showed that the total investment expense was 97.6 billion won and the cost-benefit was 4776.8 billion won, therefore a 4.8 benefit/ cost ratio was attained.

The objective of this study was to investigate the response characteristics and performance of a biofilter in the removal of ammonia, as a malodor compound. A trickle-bed type biofilter was applied for this study, and operated at the ammonia loading rate of 0.97-15.52 g/m3·h. The results of the experiment indicate that the critical loading rate of ammonia to the biofilter was 10.7 g/m3·h and the elimination capacity was 11.6 g/m3·h. The analysis of nitrogen mass balance in the reactor indicates that inlet nitrogen as gas phase was converted through the biofilter into NH4 + (41.5% by mass), NO2 - (43%), and NO3 - (15%) as the available form of nitrogen in the effluent liquid. Free ammonia concentration in the effluent liquid was estimated as being in the range from 0.14 to 2.93 mg/L (average 1.7 mg/L) during the experimental period.

This study was performed as the preliminary research to calculate the concentration of radon exposure and the annual effective dose in public hot spring bath-house. The research found that public bathhouses are the primary cause of the indoor air radon concentration inside a hot spring bathhouse. The indoor radon concentration inside a bathhouse differs significantly by region and among bathhouses in the same region, indicating that the indoor air radon concentration is affected by many factors. The annual effective indoor radon dose by exposure is estimated to range from 1.2×10−2mSv/y to 2.5×10−2mSv/y. Since this research is considered as preliminary research, further and additional relevant research to more reliably calculate the result are necessary, including accumulative research for indoor radon concentrations, and research for exposure coefficients such as the behavior patterns of public bathhouse users, etc.

This study aims to understand the correlation between odor intensity and dilution factor using the Air Dilution Olfactory Method, which is suggested in the Standard Method of Odor Compounds, by measuring odor intensity and dilution factor for fatty acids and i-butyl alcohol. For the measurement, 18 panel members were selected through a panel test, and odor intensity and dilution factor by substance produced from the selected panel were estimated. The estimation showed that the correlation of odor intensity with dilution factor for a fatty acids and i-butyl alcohol can be reasonably expressed by the equation I = A·log D + 0.5 (I : odor Intensity, D : dilution factor, A : material constant). The material constant was in order of propionic acid 2.0709, n-butyric acid 1.6006, n-valeric acid 1.3369, i-valeric acid 1.182, i-butyl alcohol 1.4326. The geometric average of increased dilution factor for the 5 compounds is about 4.8 time, 3.0 time for propionic acid and 7.0 tme for i-valeric acid due to odor intensity 1 increasing. It is suggested that the result of this study could be used as a base data for research on measures to improve the regulation standards for complex odor concentrations at a boundary sites in operation.

In this study, we numerically analyzed flow and particle transport near the electrostatic precipitator in the tunnel according to train runs. When there was no train running, flow field was formed by a precipitator. Flow emitted from precipitator blocks the path along the tunnel, and therefore most contaminated air passes through the precipitator and can be cleaned. On the other hand, flow pattern during the train run was affected by train induced wind. A strong straight flow was generated at the front of train, and back flow was formed in the opposite line. When a train runs upward only (train start from suction section to blow section), the subway train transports contaminated particles along the tunnel. For downward train runs only case, the cleaned air reentered the contaminated section with train wind. Both train runs case showed combined flow and particle concentration pattern of both single train runs.

The concentration of VOCs, NO2 was measured both inside and outside residential homes surrounding an industrial complex. Measurements were performed in the area of the industrial complexes and around 10 km away from the industrial complex area. Benzene did not exceed the air quality standard value. Toluene exhibited a high value of concentration in outdoor Yeosu investigated group. The concentration of NO2 is higher than outside concentrations of houses in both inside housing research group compared with the group of Gwangyang and Yeosu. Benzene and toluene showed high correlation (p<0.001) in the housing interior in Gwangyang, It showed a high correlation (p<0.01) in the housing interior in the comparison group. In Yeosu there was a high correlation (p<0.001) between the inside and outside of the housing in the survey group. In the control group there was only high correlation (p<0.05) in the inside of the housing.