This study was an attempt to analyze the basic analytical characteristics of octanal and nonanal compounds by TD and GC/FID system. The basic analysis (linearity, precision, MDL: method detection limit) showed similar results for VOCs in terms of QA/QC results with the same analysis system. Also, the results are sufficiently satisfy the QA/QC of the Korean odor analysis standard method. When using a polyester aluminum bag, the amount of loss was found to be about -2% to 7%. Adjusting the relative humidity and loss trend with the passage of time, the loss amount is found to be only a trace amount. With the exception of the styrene compound, all volatile organic compounds have a tendency to decrease slightly. Similar results were shown from Octanal and Nonanal. As a result, Octanal and Nonanal compound’s adsorption amount by the polyester aluminum bag was a quite small. The relative humidity and other compounds appear to be significantly unaffected by Octanal and Nonanal.

Radon (222Rn) gas is a main source of ionizing radiation of natural origin. It typically moves up through the ground to the air above and into building or home through cracks and other holes in the foundation. Significantly, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today. This survey covers the determination of indoor radon concentrations at home from 2013 to 2014 in some areas of Gangwondo, every three months (seasonal) during one year using an alpha-track detector. The results showed that the annual average concentration of indoor radon was 84.5 Bq/m3 (GM: 64.5 Bq/m3) at homes. Indoor radon level was the highest in winter and the lowest in summer. Geometric mean radon concentration in winter was 1.03~2.58 times higher than other seasons. The data obtained from this study provide a basis for the preparation of legal regulation and public health protection manuals in this area.

The study analyzed performance assessment factors of VOCs odor sensors from 3 different manufacturers, such as minimum detection limit, humidity stability and temperature stability. Through the minimum detection limit assessment, it was found that a VOCs sensor was able to detect TVOCs 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 VOCs odor sensor using photoionization could operate was between 25oC and 40oC, and the sensor output values were unstable at low temperatures. In terms of 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 odorous gases generated at 25oC. The results of the test of VOCs 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 VOCs odor sensors, all target VOCs substances had stable output values at 25oC to 40oC and at 50% to 65% relative humidities, and unstable values at low temperatures and high humidities. Therefore, the implementation of pre-treatment systems including temperature and humidity correction (25~40oC, 50~65% RH) is required for the stable use of VOCs odor sensors.

The purpose of this study is to produce the auxiliary fuel additives that will improve the heat value and reduce the odor of dried sewage sludge, an auxiliary fuel for power plants using process by-products. Through an odor analysis prior to the production of auxiliary fuel additives, it was confirmed that the main odor materials are Methylmercaptan, Acetaldehyde and Trimethylamine. Based on this, we measured the heating value on various processes by-products such as by-products of thermal power generation and by-products of refinery. In addition, the adsorption performance in the major odor material was evaluated. However, for Trimethylamine, it is very difficult to secure the reproducibility of the concentration of the standard materials as the standard material is liquid. Therefore, it was used Ammonia, which has basic property, to replace Trimethyamine. In the evaluation of various process by-products, the highest heating value in heavy oil fly ash was 5,575 kcal/kg, while in the adsorption performance evaluation, FCC was shown as having the best performance in adsorption, as it could adsorb 100% of Methylmercaptan, 47% of Acetaldehyde and 76% of Ammonia. We conducted an adsorption experiment after supporting a transition metal on the FCC in order to improve the adsorption capacity. As a result, it was confirmed the best efficiency when supporting the copper nitrate 0.5% on the FCC. Based on this result, the experiment was conducted to determine the optimal mixing ratio with a high heating value and odor reducing function using Heavy oil fly ash and FCC. The optimal mixing ratio was 90% of Heavy oil fly ash and 10% of FCC. Furthermore, it was found that the most economical performance and highest odor reducing efficiency was achieved when the mixing ratio was 90% of dried sewage sludge and 10% of auxiliary fuel additives.

The indoor air quality of residences has been regulated by designating recommended standard levels of pollutants for newly built apartments. But as of yet, no related guideline has been established for dwellings that are already occupied. From a sociological viewpoint, the gap between the rich and poor has been gradually increasing with economic development, and this has extended to the diversification of house types and living environments. Specifically, people who have the lowest income levels may live in temporary houses such as vinyl greenhouses and shanty houses, and their living environment is mostly inadequate as a result. In this study, we surveyed the indoor air quality in normal and socially vulnerable houses after the occupation stage and tried to figure out the main factors influencing indoor air quality. Airborne fungi are detected more frequently in lower living standard houses. Put another way, the concentration of airborne bacteria and the volatile organic compound levels are much higher than in normal dwellings.

Hydrogen sulfide (H2S) emitted from various sources is a major odorous compound, and non-thermal plasma (NP) has emerged as a promising technique to eliminate H2S. This study was conducted to investigate lab-scale and pilot-scale NP reactors using corona discharge for the removal of H2S, and the effects of relative humidity, applied electrical power on reactor performance and ozone generation were determined. A gas stream containing H2S was injected to the lab-scale NP reactor, and the changes in H2S and ozone concentration were monitored. In the pilotscale NP experiment, the inlet concentration and flow rate were modified to determine the effect of relative humidity and applied power on the NP performance. In the lab-scale NP experiments, H2S removal was found to be the 1st-order reaction in the presence of ozone. On the other hand, when plasma reaction and ozone generation were initiated after H2S was introduced, the H2S oxidation followed the 0th-order kinetics. The ratio of indirect oxidation by ozone to the overall H2S removal was evaluated using two different experimental findings, indicating that approximately 70% of the overall H2S elimination was accounted for by the indirect oxidation. The pilotscale NP experiments showed that H2S introduced to the reactor was completely removed at low flow rates, and approximately 90% of H2S was eliminated at the gas flow rate of 15 m3/min. Furthermore, the elimination capacity of the pilot-scale NP was 3.4 g/m3·min for the removal of H2S at various inlet concentrations. Finally, the experimental results obtained from both the lab-scale and the pilot-scale reactor operations indicated that the H2S mass removal was proportional to the applied electrical power, and average H2S masses removed per unit electrical power were calculated to be 358 and 348 mg-H2S/kW in the lab-scale and the pilot-scale reactors, respectively. To optimize energy efficiency and prevent the generation of excessive ozone, an appropriate operating time of the NP reactor must be determined.

In the current study, oxidative decomposition of a volatile organic compound was investigated at room temperature and pressure. The experiment was carried out in lower ethylene concentration and with various higher gas flow rates. The reactor has 7 different compartments in which the reaction takes place independently. Plasma was generated inside each compartment by the application of alternating current (AC) voltage. 5 wt% manganese loaded and 5 wt% silver loaded 13X zeolite were used as catalysts. Bare zeolite showed higher ethylene decomposition efficiency than Ag loaded and Mn loaded zeolite. Ozone concentration was increased slightly while increasing the SIE, reached a maximum and started decreasing. Ag loaded zeolite also showed similar decomposition efficiency, but the concentration of ozone was greatly lowered.

The objective of this study was to assess RF-EMF exposure levels in indoor daycare centers in a Metropolitan city. RF-EMF measurements were collected and surveyed from 50 volunteer daycare centers in the Korea between October 2013 and October 2014. Through our research, it was found that the main exposure source for indoor daycare centers is the frequency bands for TV and Radio broadcasting (FM: 88.1~107.9 MHz), mobile phone (869~894 MHz, 1840~1870 MHz, 1885~2170 MHz), wireless LAN and home electronics, etc., including TRS, Wireless Data Communication. The RF-EMF exposure levels for all daycare centers were far below the recommended standards of EMF Guideline Korea and international reference levels proposed by ICNIRP (International Commission on Non-Ionizing Radiation Protection). However, in terms of long term health effects some uncertainty exists, and thus minimizing exposure may reduce this uncertainty. The data we collected will be useful data for determining RF-EMF management and risk communication at daycare centers.

About half of the South Korean population lives in the three major metropolitan areas, which are Seoul, Kyeonggi and Incheon. Among this group, more than 50% live in apartments. In this study, the relationship between the concentration of indoor VOCs and environmental factors was investigated in metropolitan apartments in the occupation stage. The maximum concentration of TVOC (total volatile organic compounds) was monitored in spring season. Among the identified VOCs, toluene was present in the highest amount, followed by terpene, aldehyde and hydrocarbon. Due to the specific indoor sources, the I/O ratio of terpene (e.g. d-limonene, α-pinene, and β-pinene) was relatively higher than that of the others. The construction year and length of residence were revealed as the environmental factors having the greatest influence on the concentration of indoor benzene, toluene, ethylbenzene, xylene, styrene and hydrocarbon, and the relationship was statistically significant. The floor and size of the apartment influenced the levels of indoor nonanal. The relationships between individual VOCs showed highly positive correlations that are statistically significant. Through the relationship study, it was found that factors including newly built apartment, short period of time after moving in, high floors and small floor area were the main factors inducing an increased concentration of indoor VOCs in apartments.

We measured VOCs and NO2 in the indoor and outdoor air at 125 houses in Jeollanam-do and Gyeongsangnamdo, from March 2007 to January 2008. The concentration of benzene measured in the Gwangyang survey group was higher than in Yeosu and Hadong, and showed a statistically significant difference from Yeosu (p<0.05). The concentration of toluene in outdoor air was highest in the Gwangyang survey group. The concentration of NO2 measured in the Yeosu survey group was higher than in Gwangyang and Hadong, and showed a statistically significant difference from Hadong (p<0.01). According to the results of a correlation analysis, VOCs (benzene, toluene, xylene, ethylbenzene) exposure of individuals showed a significant correlation with the residential indoor air (p<0.01). Also, VOCs of residential indoor and outdoor air showed a significant correlation (p<0.01). The concentration of NO2 exposure of individuals measured in the Yeosu comparison group showed a high correlation with the residential indoor air.