Recently, Advanced water treatment facilities with Ozone are being introduced domestically. However, waterproofing/corrosion prevention construction method of concrete structure for existing advanced water treatment makes waterproofing/corrosion prevention materials and concrete deteriorated because of strong oxidation of ozone. Therefore, in this study, It was evaluated in ozone resistance and bond strength of metal spraying coating.

Sensitivity analysis of the WRF model according to the impact of nudging (e.g., nudging techniques and application domains) was conducted during high nocturnal ozone episode to improve the prediction of the regional ozone concentration in the southeastern coastal area of the Korean peninsula. The analysis was performed by six simulation experiments: (1) without nudging (e.g., CNTL case), (2) with observation nudging (ONE case) to all domains (domain 1∼4), (3) with grid nudging (GNE case) to all domains, (4)∼(6) with grid nudging to domain 1, domain 1∼2 and domain 1∼3, respectively (GNE-1, GNE-2, GNE-3 case). The results for nudging techniques showed that the GNE case was in very good agreement with those observed during all analysis periods (e.g., daytime, nighttime, and total), as compared to the ONE case. In particular, the large effect of grid nudging on the near-surface meteorological factors (temperature, relative humidity, and wind fields) was predicted at the coastline and nearby sea during daytime. The results for application domains showed that the effects of nudging were distinguished between the meteorological factors and between the time periods. When applied grid nudging until subdomain, the improvement effects of temperature and relative humidity had differential tendencies. Temperature was increased for all time, but relative humidity was increased in daytime and was decreased in nighttime. Thus, GNE case showed better result than other cases.

본 연구는 고 에너지 방사선 조사에 기인된 방사선치료실 내 오존 농도의 변화를 비교·분석하고자 하였 다. 이를 위하여 치료실 주변 대기 중 오존 농도와 치료실 내 배경 오존 농도를 분석하여 고 에너지 방사선 조사에 기인된 치료실 내 평균 오존 농도를 비교하였다. 치료실 내 배경 오존 농도는 평균 17.4±7.9ppb로 방사선치료실 주변의 대기 중 오존 농도(평균 36.8±22.3ppb)보다 약 50% 정도 통계적으로 유의하게 낮게 나타났다(p<0.05). 고 에너지 방사선 조사에 기인된 치료실 내 오존 농도는 방사선이 조사됨과 동시에 배경 오존 농도의 약 2배 수준으로 급격하게 증가되었으며 조사시간이 증가함에 따라 기울기가 일정한 증가 추 이를 보이다가 약 130초에서 180초 부근에서 최대 오존 농도를 이루고 점차 포화되는 경향을 보였으며 배 경 오존 농도로 감소하는데 소요되는 시간은 약 10분 이상이었다. 본 연구 결과를 토대로 고 에너지 방사 선 조사에 기인된 방사선치료실 내 오존 농도는 후각을 자극하는 오존의 특이한 냄새를 맡거나 순간적인 호흡 곤란과 마른기침으로 가슴 통증 등의 신체적 증상이 나타날 수 있는 수준으로 밀폐된 방사선치료실 에서 고농도 오존에 장시간 노출될 경우 폐 질환을 악화시킬 수 있기 때문에 각별한 주의가 요구된다.

Since prolonged exposure to elevated ozone (O3) concentrations is known to be harmful to human health, appropriate control strategies for ozone are needed for the non-attainment area such as Seoul, Korea. The goal of this research is to assess factors linked with the 1-hour ozone exceedance through a decision tree model. Since ozone is a secondary pollutant, lag times between ozone and explanatory variables for ozone formation are taken into account in the model to improve the accuracy of the simulation. Results show that while ozone concentrations of the previous day and NO2 concentrations in the morning are major drivers for ozone exceedances in the early afternoon, meteorology plays more important role for ozone exceedances in the late afternoon. Results also show that a selection of lag times between ozone and explanatory variables affect the accuracy of predicting 1-hour ozone exceedances. The result analyzed in this study can be used for developing control strategies of ozone in Seoul, Korea.

A comparison of ozone simulations in the seoul metropolitan region (SMR) using the community multiscale air quality (CMAQ) model with SAPRC99 and CB05 chemical mechanisms (i.e. EXP-SP99 and EXP-CB05) has been conducted during four seasons of 2012. The model results showed that the differences in average ozone concentrations between the EXP-SP99 and EXP-CB05 were found to be large in summer, but very small in the other seasons. This can be attributed that the SAPRC99 tends to produce more ozone than the CB05 in urban area like the SMR with low VOC/NOx ratio under high ozone conditions. Through quantitative comparison between two mechanisms for the summer, it was found that the average ozone concentrations from the EXP-SP99 were about 3 ppb higher than those from the EXP-CB05 and agreed well with the observations. Horizontal differences in ozone concentrations between SAPRC99 and CB05 showed that significant differences were found in southern part of the SMR and over the sea near the coast in summer.

Comparing to the other air pollutants like SO2, CO, the number of exceedance of the ozone national ambient air quality standard(NAAQS) and the ozone warning increased recently in Busan. The purpose of this study is to find out the preliminary symptoms for high ozone days in Busan area. In order to find out the preliminary symptoms, the hourly ozone data at air quality monitoring stations and the hourly meterological parameters at Busan regional meteorological 2007 to 2013 were used for the analysis. Averaged daily max ozone concentration was the highest(0.055 ppm) at Noksan and Youngsuri in the ozone season from 2007 to 2013. The horizontal distributions of daily max. ozone including all stations in Busan at high ozone days(the day exceeding 0.1 ppm of ozone concentration at least one station) were classified from two to five clusters by hierarchial cluster analysis. The meteorological variables showing strong correlation with daily max. ozone were the daily mean dew point temperature, averaged total insolation, the daily mean relative humidity and the daily mean cloud amount. And the most frequent levels were 19-23℃ in dew point temperature, 21-24 MJ/m2 in total insolation on the day before, 2.6-3.0 MJ/m2 on the very day, 67-80% in relative humidity and 0-3 in cloud amount.

In this study, the regional climate (WRF) and air quality (CMAQ) models were used to simulate the effects of future urban growth on surface ozone concentrations in the Seoul metropolitan region (SMR). These analyses were performed based on changes in ozone concentrations during ozone seasons (May–June) for the year 2050 (future) relative to 2012 (present) by urban growth. The results were compared with the impacts of RCP scenarios on ozone concentrations in the SMR. The fractions of urban in the SMR (25.8 %) for the 2050 were much higher than those (13.9 %) for the 2012 and the future emissions (e.g., CO, NO, NO2, SO2, VOC) were increased from 121 % (NO) to 161.3 % (NO2) depending on emission material. The mean and daily maximum 1-h ozone in the SMR increased about 3 - 7 ppb by the effect the RCP scenarios. However, the effect of urban growth reduced the mean ozone by 3 ppb in the SMR and increased the daily maximum 1-h ozone by 2 - 5 ppb over the northeastern SMR and around the coastline. In particular, the ozone pollution days exceeding the 1-h regulatory standard (100 ppb) were far more affected by urban growth than mean values. As a result, the average number of days exceeding the 1-h regulatory standard increased up to 10 times.

The objective of this study was to find optimum pretreatment conditions of ozone and microwave for solubilizationof thickened waste activated sludge (TWAS). Response surface analysis was applied to determine the combination of ozoneconcentration (0.03 to 0.1g O3/g total solid (TS)) and microwave temperature (100~170oC). The temperature significantlyaffected the solubilization degree of sludge (p<0.01). Within the design boundaries, the conditions predicted to maximizethe solubilization degree of 41.6% were determined to be 0.065g O3/g TS and 170oC. On the other hand, the solubilizationdegree with the ozone pretreatment alone was 2.7 to 12.2% at 0.03~0.1g O3/g TS. The results show that the combinationof ozone and microwave pretreatments is effective in solubilization of TWAS.

This study analyzes the characteristics of ozone weekend effect(OWE) in Busan. O3 concentration on Sunday was over 10% higher than that on weekdays in all areas except for Kwangbokdong, Taejongdae, and Joadong. Such a difference was higher in the industrial area than in the residential area. O3 generation was facilitated by the decrease in NOx emission on Sunday in VOC-limited regime where the VOC/NOx ratio is low. Low NO concentration in the Sunday morning decreased inhibition of O3. NO-O3 crossover time on Sunday was shorter than that on weekdays which in turn extended the accumulated duration of O3. Future studies can include whether the entire Busan is VOCS-limited or the coastal area is VOCS-limited while the inland area is NOX-limited.

최근 수질오염의 악화로 고도정수처리시설에 대한 수요가 커지고 있으며, 오존처리와 같은 밀폐형 고도정수처리시설의 설치가 늘고 있는 실정이다. 그러나 오존의 강력한 산화작용으로 인해 콘크리트 구조물의 침식이 우려됨에 따라 오존에 대응 가능한 에폭시 방수방식재가 콘크리트 표층부 보호 코팅재로 적용되고 있다. 그러나 이러한 에폭시가 오존에 대한 성능수준 및 장기적 내구성을 명확히 측정할 방법과 기준이 없어 정확한 품질관리가 이루어지지 않고 있는 실정이며, 이로 인해 수처리용 콘크리트 구조물의 장기내구성 확보에 대한 우려가 제기되고 있다. 이 연구에서는 AFM과 나노인덴테이션 기법이 기존에 사용하던 평가방법인 육안관찰, 중량변화, 표면관찰, 색차분석 등의 간접적 평가방법과 함께 에폭시 방수방식재 평가방법으로써의 적합한지를 판단하고자 하였으며, 이를 위해 오존용으로 개발된 6종의 다른 성분으로 구성된 에폭시계 방수방식재를 대상으로 열화특성을 분석하였다. 연구결과 AFM과 나노인덴테이션을 활용할 경우 기존 평가방법보다 직접적이고 정량적인 평가가 가능함을 확인하였으며, 일부 에폭시 코팅재료의 경우 오존에 대한 성능 한계치 (임계치)를 명확히 확인할 수 있었다.

The exposed population of a vulnerable group to high ozone episodes (exceeding 60 ppb/8h) was estimated in Busan metropolitan city from 2000 to 2010. The frequency of high ozone days at monitoring sites and the number of the population aged over 65 were used to calculate the accumulated (total, seasonal, and yearly) number of the exposed older population (EOP) to high ozone episodes during the study period based on administrative areas, by interpolation and zonal mean methods in ArcGIS software. The older population in this city had increased significantly from 2000 to 2010 (representing over 10% of the total population in 2010). The vulnerable areas (e.g. the eastern area of the city) of the EOP to high ozone episodes were different from the areas with frequent high ozone episodes (e.g., the western area) due to the increase of the older population in particular areas. The difference was more significant in spring than in any other season, and in 2010 than in previous years (2000 and 2005).

In this study, in order to confirm whether the deterioration of the concrete structure in contact with ozone and establish a countermeasure for the deterioration, the test of concrete in ozone were conducted by using a few concrete specimen that is fitted to the capacity of the test equipment.

This work investigates the relationship between the sea breeze circulation and ozone concentrations during cold water events in the southeastern coastal area of the Korean Peninsula, where coastal upwelling frequently occur. This analysis was performed based on the classification of two categories, such as cold water and non-cold water events, over the period of 2000-2009. The low air temperature (0.5℃), low SST (5℃) and the wind direction(southerly) are the features of the cold water events in the Southeastern coastal area. Moreover, ozone concentrations in the cases of the sea breeze circulation and cold water events were significantly lower (below 30 ppb) than those (70∼100 ppb) in the non-clod water events, because of the low air temperature (10∼20℃) and high wind speed (3∼5 m/s) around the southeastern coastal area.

Ozone concentrations in water and air, and resulting disinfective properties, were measured following generation by either an ozone generator or a low-temperature dielectric barrier discharge plasma generator. In freshwater, ozone concentrations of 0.81 and 0.48 mg/L O3 were observed after the ozone and plasma generators had been operated for five minutes, respectively. Higher levels of dissolved O3 were attained more easily with the ozone generator. In seawater, both systems were capable of creating concentrations greater than 3.00 mg/L O3 after 5minutes of operation. Higher ozone levels were attained more easily in seawater than in freshwater. Rates of bacterial sterilization in seawater after three minutes were 96% and 88%, using the plasma and ozone generators, respectively. In freshwater, higher concentrations of ozone were released into the atmosphere by the ozone generator than by the plasma generator. In creating equivalent levels of dissolved ozone in freshwater, the plasma generator released 4.5 times more ozone into the atmosphere than did the ozone generator. This shows that ozone generators are more effective than plasma generators for creating ozonated water. For the same concentration of dissolved ozone in seawater, more ozone was released into the atmosphere using the ozone generator than using the plasma generator. Therefore, with regard to air pollution, plasma generators seem to be less expensive than ozone generators.

This study, changes in raw water quality is to indicate on the efficiency of ozone treatment of each pollutant as compared to derive the appropriate operating measures. The appropriate selection for injection rate of pre-ozone and did not inject pre-ozone assess changes in the water. When good water quality, you not injected of pre-ozone to evaluate the economic efficiency of electricity and put the most cost-effective ozone concentration were evaluated. Evaluation remove organic matter and chlorophyll-a concentration level in experiments with each factor of the water DOC> 2.5 ㎎ / L, THMFP> 70 ㎍ / L, Chl-a> 30 ㎎/ ㎥or less constant process, if you do not need to put pre-ozone showed little impact. It also does not put you in pre-ozone appropriate produce enough power rate savings was calculated as approximately 90 million won. Ability to remove organic materials and the ability to produce disinfection byproducts, and cost-effective decisions by considering the concentration of injection if pre-ozone 1 mg/L was investigated by the appropriate concentration of ozone injection.

This study utilized atomic force microscopy (AFM) and nanoindentation methods to evaluate epoxy water-resistance and anti-corrosiveness. This study considered two different epoxy formulations to assess typical degradation characteristics of epoxy surfaces with regard to water-resistance and anti-corrosiveness. As a result, this study was able to clearly confirm changes in physical characteristics and performance tendencies regarding ozone oxidizing reactions.

We studied the ozone concentrations generated by low-temperature dielectric barrier discharge plasma reactor after adding air and phytoplankton to control the ozone concentrations in seawater. We also examined the numbers of bacteria and Vibrio spp. after treatment using the plasma reactor. As the airflow rate was increased, more ozone was removed. Although marked variation in the ozone decrease was observed with and without airflow, the rate of ozone removal did not increase proportionately with the airflow rates. The ozone concentration decreased with increasing organic matter and time. The amount of organic matter seems to be an important factor decreasing the dissolved ozone concentration in liquid. The ozone concentration was 0.07, 0.32, 1.28, and 2.3 mg/L when operating the plasma reactor for 30, 60, 180, and 300 s, respectively; i.e., the ozone concentration increased with the reactor operating time. The initial numbers of bacteria and Vibrio spp. were 800 and 480 CFU/mL, respectively. After operating the plasma reactor at a flow rate of 6 L/min for 30 s, no bacteria or Vibrio spp. were detected. The disinfection effect of this plasma reactor seems to be superior to that of a conventional ozone generator.

Ozone is the secondary photochemical pollutant formed from ozone precursor such as nitrogen dioxide and non-methane volatile organic compounds(VOCs). The ambient concentration of ozone depends on several factors: sunshine intensity, atmospheric convection, the height of the thermal inversion layer, concentrations of nitrogen oxides and VOCs. Busan is located in the southeast coastal area of Korea so the ozone concentration of Busan is mainly affected from the meteorological variables related to the sea such as sea breeze. In this study the ozone concentrations of Busan in 2008~2010 were used to analyse the cause of the regional ozone difference in eastern area of Busan. The average ozone concentration of Youngsuri was highest in Busan however the average ozone concentration of Gijang was equal to the average ozone concentration of Busan in 2008~2010. The two sites are located in eastern area of Busan but the distance of two sites is only 9km. To find the reason for the difference of ozone concentration between Youngsuri and Gijang, the meteorological variables in two sites were analyzed. For the analysis of meteorological variables the atmospheric numerical model WRF(Weather Research and Forecasting) was used at the day of the maximum and minimum difference in the ozone concentration at the two sites. As a result of analysis, when the boundary layer height was lower and the sea breeze was weaker in Youngsuri, the ozone concentration of Youngsuri was high. Furthermore when the sea breeze blew from the south in the eastern area of Busan, the sea breeze at Youngsuri turned into the southeast and the intensity of sea breeze was weaker because of the mountain in the southern region of Youngsuri. In that case, the difference of ozone concentration between Youngsuri and Gijang was considerable.

In order to clarify the impact of emissions reductions on the air quality over Metropolitan area of Korean Peninsula, several numerical experiment and analysis of integrated process rate(IPR) of ozone were carried out. Numerical models used in this study are WRF for the estimate the meteorological elements and CMAQ for assessment of ozone concentration. As result in the sensitive test of VOC/NOx reduction experiments, although VOC reduction tends to induce the different impact on the advection and photochemical reaction rate of ozone in urban area and rural area, the mechanism of ozone appeared to be more sensitive to the reduction of VOC than that of NOx over the metropolitan and its surround area. So the control of VOC emission inventories is an effective means to decrease the ozone concentrations around this area.

최근 수자원 내에서 미량오염물질이 번번히 발견되고 있고(Lee, 2012) 이중 항생제 내성도 하나의 미량 오염물질로 간주 될 수 있다. 수자원내 항생제 내성 유전자는 환경 내 항생제 내성균의 증가를 일으켜 궁극적으로 병원균 내의 항생제 내성균의 증가를 초래할 수 있다(Kim et al., 2010). 소독은 병원성 미생물 및 잠재적 위해성을 가진 미생물을 불활성화 시키기 위한 공정이며, 수처리 공정에서 소독방법은 염소소독, 오존, UV 또는 전자빔이 선택되어 왔다(Gehr et al., 2003). 본 연구에서는 강력한 산화 기법중의 하나인 오존 소독과 전통적 기법인 염소소독을 비교하는데 목적이 있다.