Seoul is one of the most dynamic capital cities in the world of which population is about 10.49 million. The air quality of Seoul subway is a great concern to users and the public authorities, especially the pollution of particulate matters. The metallic particulate matters are generated from the friction of wheels and subway rails, which causes dispersion into the platform and even to the trains. This study attempted to characterize the current filters in subway MVAC system and a newly developed filter which was a type of thin electret fiber bundle. Collection efficiency of the filtration system varies from 20% to 90% depending on filter life and dust particle size. The removal of fine dust with diameter smaller than 1㎛, which could not be well achieved by current filtration system, is very important in the subway air cleaning system. The new electret filter was found to have a high potential for the use in subway MVAC with high collection efficiency, especially for fine mode dust.

This paper presented experimental results for photocatalytic air cleaner removal performance for malodorous compounds generated from rest room. Photocatalytic oxidation (PCO) efficiency was up to 80∼ 90% for NH₃ in chamber, 29.3% for H2S, 79.6% for CH3SH, 58.8% for DMDS individually. PCO efficiency for DMS(Dimethy Sulfide) and DMDS(Dimethyl Disulfide) were relatively lower than that of NH₃ and CH3SH, this results indicate that DMS and DMDS removal process were effected by by-products of photocatalytic oxidation and humidity. Ozone was relatively low (below 5ppb) under the test conditions through photocatalytic oxidation. It is necessary to test a reliability of the air cleaner for a longtime under the various indoor conditions. But, prototype photocatalytic air cleaner will promise useful air cleaner for indoor air quality applications.

Indoor air quality can be affected by indoor sources, ventilation, decay and outdoor levels. Although technologies exist to measure these factors, direct measurements are often difficult. Toluene and nitrogen dioxide (NO₂) concentrations of residential indoor and outdoor were simultaneously measured and compared in 16 houses, using passive samplers during every 3 days for 60 days. Concentrations of toluene and NO₂ were analyzed by gas chromatography and spectrophotometer, respectively. Using a mass balance model, penetration factor (ventilation rate divided by sum of ventilation rate and deposition constant) and source generation factor (source generation rate divided by sum of ventilation rate and deposition constant) were calculated by multiple indoor and outdoor measurements. The mean contributions of toluene of indoor and outdoor sources on residential indoor air quality were estimated to be 31.01% and 67.00%, respectively. On the other hand, mean contributions of NO₂ were 58.93% and 41.06%, respectively. These results could be explained that contributions of indoor and outdoor air pollutants sources are different to residential indoor air concentrations. In conclusion, contributions of outdoor air and indoor sources affecting indoor air quality were effectively characterized using multiple indoor and outdoor measurements.

The information about time spent in microenvironments plays a critical role for an exposure assessment of the person concerned, considering the personal exposure relies on the characterization of activity patterns of the population at risk and human activities impact the timing, location, and level of personal pollutant exposure. The purposes of this paper were to present indoor time activity patterns of Korean from a population-based study and to determine individual factors of time spent in microenvironments. The population based study collected time activity pattern of about 32,000 Korean for two consecutive days. The mean times spent at home, other indoors, outdoors, and transportation in related to the whole sample of 19.025 people are 14.23hrs(59.3%), 6.80hrs(28.3%), 1.26hrs(5.2%), and 1.75hrs(7.3%) in weekday, respectively. Database provides information on how the proportion of persons in different locations changes by time of day in weekday. Here, we see that over 90% of respondents were in a residence from about 11 PM to 5 AM, and the largest proportions of respondents in offices, factories, schools and public buildings occur between 8 AM and 5 PM.

Since equipment currently being used in the department of radiological technology in hospitals comes into contact with patients carrying diseases, there inevitably will be the existence of pathogenic bacteria. Therefore, in order to increase the importance of using disinfectant in hospital infection precaution and the recognition of hospital infection management, comparisons were made by measuring the bacterial contamination levels in radiology room within the department of radiological technology and comparing the measurements with post disinfection levels. Disinfecting the rooms from detected bacteria was conducted with water, tissue cleaner, or 70% alcohol. When measuring bacterial contamination levels in radiology rooms, a variety of bacteria was detected. When disinfecting the interior of radiology rooms the effectiveness of destroying bacteria and preventing hospital infection was greatest when using 70% alcohol compared to water, tissue cleaner and ventilation. Therefore, there needs to be a development of a better antiseptic for destroying bacteria because there is a possibility for hospital medical equipment to be constantly contaminated. Efforts need to be made to prevent hospital infections and patient secondary infection by disinfecting and sterilizing equipment.

In this study, toluene catalytic oxidation was investigated using various metal components (Cu, Ce, Ni, La and Zr) supported on Used FCC zeolite for the application of the waste recycling and odor reduction. Among the metals, 5 wt% Cu/zeolite showed the best catalytic activity. 100 % conversion was achieved at 300℃ which was 50℃ lower than that of other metal components. As increasing the amount of doped Cu, the CuO was formed and the surface area and pore size were decreased. By the reduction treatment before toluene oxidation, the catalytic activity of the oxidation below 250℃ was improved. No decrease of conversion was observed during the continuos reaction at 300℃ for 48 h.

In this study, catalytic decomposition of chlorobenzene, a model compound of dioxin, was investigated. Catalysts made of a mesoporous material SBA-15 were used. The effect of Pt impregnation on the catalytic activity was evaluated. The catalysts were characterized using BET and NH₃-TPD. The catalytic activity for chlorobenzene removal reaction was shown to increase with the acid amount of catalysts. Addition of Pt to Al-SBA-15 was also shown to enhance the catalytic activity.