This study focused on evaluating the efficiency of the removal of non-point source pollution by Daecheong Lake Juwon Stream constructed wetlands. The constructed wetland system is a surface flow type designed in the year 2007 for purifying eutrophic water of Daecheong Lake Juwon Stream. The value of conductivity, suspended solids(SS), chemical oxygen demand using a potassium permanganate(CODMn), five-day biochemical oxygen demand(BOD5), total nitrogen(T-N), total phosphorous(T-P), and pH in inflow averaged 220.2, 2.46, 3.33, 1.34, 2.00, 0.04 mg/L and 7.24, respectively and in outflow averaged 227.9, 1.12, 3.34, 0.87, 1.16, 0.02 mg/L and 7.45, respectively. The average removal efficiency of constructed wetlands was 30 % for SS, 22 % for BOD5, 45 % for T-N and 31 % for T-P. The removal rates of SS, BOD5 and T-N in the spring, summer and autumn were higher than those in winter. The removal rate of T-P was not significant different in all seasons. The amounts of pollutants removal in the constructed wetlands were higher in the order of 3rd ‹ 2nd ‹ 1st wetland for SS and T-P, 2nd ‹ 3rd ‹ 1st wetland for BOD5 and T-N. Therefore, our findings suggest that the constructed wetlands could well treat the eutrophic Daecheong Lake Juwon Stream waters.
Urban areas (residential, commercial, transportation), each of the points during the same rainfall in the same area, this study was evaluated by a survey to find out the basic data and the characteristics of non-point pollution on local characteristics was performed. To evaluate and compare a non-point source pollution concentrations. The conclusion of this study was to know the influence of non-point pollutants in initial rainfall. There was a difference during the same point was compared. The pollution levels were differences in the point-specific characteristics, the same point compared by rainfall when rainfall is low, the contaminant concentrations were high. Finally, when compared to the number of rainy days. The shorter the number of rainy days, the non-point pollutants were high.
We have performed CFD simulation and analyzed flow and concentration fields for the basic data of the ventilation system for removing pollutants which were produced in a lecture room. The flow patterns indicated differently according to the arrangement of openings and the concentration distribution of pollutants were showed higher and lower because of the effect of that flow patterns. In the case of arranging the openings to the upper and lower side, the stagnation appearance of flow formed in the interested space. In the case of arranging the openings to the right and left side, the stagnation of high concentration pollutants appeared in the middle area of the interested space. On the increasing exhaust velocity, the distribution of pollutants appeared similar to the normal case, but the concentration of pollutants were lower.
Tuberculation and slime accumulated in water mains play an important role in modifying water quality of drinking water. Therefore, in this study, it was investigated that what materials were accumulated, and what components were included in the tuberculation and slime of water mains. The Various tuberculation and slime sample were collected from the 12 water mains to analyze their physical and chemical properties and crystal structure. As a analysis method, VSS(Volatile suspended solid), SEM(scanning electron microscope), EDS(Energy Dispersive X-ray spectroscope), ICP(Inductively Coupled Plasma Mass Spectrometer) and XRD(X-Ray Diffractomete) were used. The results of analysis on the samples, the representative materials were verified such as iron corrosion products, the fine sand particles generated during backwash, fine particles of activated carbon, aluminum used in coagulation process, and manganese included in raw water.
Hazardous air pollutants such as NO2, VOCs and PM10 were measured Daegu, Korea in major micro-environments,where housewives spend the most of their time, and personal exposure times were estimated by using time activitypatterns and exposure scenarios. The major microenvironments of housewives were selected using the ‘Time-UseSurvey’ conducted by the National Statistical Office in Korea in 2009. A total of 4,514 (weekdays) and 3,063(weekends) housewives were recruited for the ‘Time-Use Survey.’ It seems that housewives are spending about80% of their time in the house, and about 5% of their time outdoors during weekdays and weekends. The indoor/outdoor ratio of the average concentration of NO2 was more than 1, which indicated that the source was indoors.Toluene was shown to have higher concentrations indoors than outdoors. Ethylbenzene and xylene displayedsimilar characteristics to toluene, and the concentration ratio for indoor/outdoor was shown to be 1.29 ± 0.76 and1.04 ± 0.45, respectively, higher concentrations indoors. Based on the results of the time activity patterns ofparticipants, 3 kinds of exposure scenarios were formulated. The spent time and air concentration in eachenvironment were assumed as normal and lognormal distribution, respectively. And then the Monte-Carlosimulation was conducted. According to the result of the simulation, the exposures to hazardous air pollutantsrevealed an increasing pattern as housewives visits other indoor environments such as supermarkets.
본 연구는 시설하우스에서 비점오염원으로 인해 배출되는 오염된 농업배수를 인공습지에서 효과적으로 처리하기 위한 기초자료를 확보하기 위해 인공습지에서 여재종류, 조합방법 및 부하량에 따른 오염물질 정화효율을 평가하였다. 인공습지의 조합방법은 수직-수평흐름조, 수평-수직흐름조, 수평-수직-수평흐름조 및 수직-수평-수평흐름조로 구분하여 설계 및 시공하였으며, 여재는 왕사, 쇄석, 방해석 및 혼합여재로 구분하여 각 조에 충진하였다. 또한 농업배수 부하량을 150, 300, 600 L m-2 day-1으로 달리하여 오염물질의 처리효율을 조사하였다. 조합방법별 수처리효율은 HF-VF-HF 조합방법이 다른 조합방법에 비해 높은 처리효율을 보였으며, 최적여재는 COD 처리효율은 왕사가 가장 높았고, T-N은 쇄석, T-P는 방해석이 가장 높았다. 하지만 모든 처리효율과 경제성 부분을 고려하였을 때 최적여재는 혼합여재가 가장 효과적일 것으로 판단된다. 농업배수의 부하량에 따른 처리효율 결과 COD는 농업배수 부하량 600 L m-2 day-1까지 안정적인 처리효율을 보였으나, T-N 및 T-P는 150 L m-2 day-1≒300 L m-2 day-1¤600 L m-2 day-1의 순으로 농업배수의 부하량이 증가함에 따라 약간 감소하는 경향이었다. 따라서 시설하우스 농업배수 처리를 위한 인공습지 농업배수처리장의 최적조건은 HF-VH-HF 조합형 인공습지에 왕사, 쇄석 및 방해석이 혼합된 혼합여재로 충진하고 부하량 300 L m-2 day-1 이하의 농업배수를 주입하는 것이 최적일 것으로 판단된다.
지구 대기에서의 편광 현상을 촬영하기 위해 태양이 지평선에 걸친 순간 편광필터와 전천 카메라를 이용하여 전천 사진을 촬영하였다. 사진으로부터 편광 현상에서의 편광비와 편광폭을 정의하고 이를 측정하는 방법을 개발하였다. 편광비와 편광폭의 시계열 촬영을 통해 기상 조건에 따라 매일 달라지는 편광 현상을 정량적으로 분석할 수 있게 되었고, 이것이 기상 요소 중 대기 오염 물질과 의미 있는 상관 관계를 보이고 있다는 것을 확인하였다. 대기 편광 현상은 대기 중 대기 오염 물질의 영향을 받는데 오염 물질이 많을수록 편광비는 작아지고 편광폭은 커지는 경향을 보였다. 이는 오염 물질이 광자를 더욱 산란시켜서 편광 현상을 관찰하는 하늘의 넓은 영역으로 퍼지게 하는 효과인 것으로 추측한다.
식품오염물질에 관련한 연구가 많이 진행되었지만 대부분 단기적 과제이었기에 식품오염물질 관리를 위한 종합 적이고 체계적인 연구가 필요하다. 본 연구에서는 식품오염물질 향후 연구방향을 제안하기 위하여 델파이 조사를 실시하였으며, 중요도 및 시급성을 고려하여 우선순위를 설정하였다. 학계, 연구기관, 정부기관, 기업 등 다양한 소속에 있는 50명의 전문가를 대상으로 식품안전과 관련한 개 방형 질문을 하였으며, 161개의 필요연구항목을 도출하였다. 이를 분류하여 5개 분야, 42개 항목으로 구성된 설문 지를 작성하였다. 5개 분야는 ‘식품오염물질 통합관리 시스템’, ‘환경유래 식품오염물질 안전관리’, ‘식품 중 오염된 자연독소 안전관리’, ‘조리가공 중 생성된 식품유해물질 안전관리’, ‘국내외 식품오염물질 안전관리 협력체계 구축 및 교육·홍보 방안’ 이었다. 전문가들이 답한 설문지(30/ 50 응답)를 분석하여 필요연구의 우선순위를 설정하였으며, 전문가들의 합의단계를 거쳐(24/30 응답) 이를 확정하였다. 본 설문조사 결과는 식품오염물질 안전관리를 위한 연구방향을 설정하기 위한 기초자료로 사용할 수 있을 것 이라 사료된다.
We estimated decreasing rate of indoor air pollutants with are airborne bacteria, airborne fungi, formaldehyde, total volatile organic compounds, PM10, and PM2.5 in 10 children’s hospitals and 6 childbirth houses located in Seoul and Gyeonggi-do from November to December in 2012. Sectional period was respectively divided for operating and non-operating the air cleaners. There was a trend that concentration of surveyed pollutants in children’s hospitals and childbirth houses during operating period decreased among indoor air. We used Monte-Calro simulation to remove uncertainty and identify efficiency of eliminated pollutants such as surveyed pollutants by the air cleaners. Average efficiency of removal were 61.39 ± 21.42% for airborne bacteria, 71.77 ± 19.65% for airborne fungi, 73.37 ± 24.62% for formaldehyde, 71.20 ± 25.96% for total volatile organic compounds, 65.16 ± 23.80% for PM10, and 71.06 ± 23.97% for PM2.5.
본 연구는 강우시 불투수성 지역에서 비점오염원 유출 특성을 분석하기 위하여 수행되었다. 불투수성 지역의 강 우사상 특성은 강우강도에 대한 영향을 많이 받는 것으 로 나타났으며, 강우강도가 크게 작용하면, 초기강우 현 상이 잘 일어나는 것으로 나타났다. 또한 선행무강우일수 에 의해서 비점오염물질의 농도차가 큰 것으로 나타나, 이에 대한 대책 마련이 필요할 것으로 판단된다. 불투수 성 지역의 비점오염원 유출 경향을 보면, 강우초기 유출 유량에 포함되어 유출되는 오염물질의 농도가 상대적으 로 매우 높게 나타났고, 일정 시간 경과 후에는 지속되는 강우에도 불구하고 오염물질의 농도는 증가하지 않고 낮 은 농도로 안정적인 유출경향을 나타내었다. 이러한 이유 는 건기 시 도로 표면에 집적되어 있던 오염물질들이 강 우시 초기에 유출되어 비점오염물질의 농도가 높게 나타 나는 것으로 나타났다. 불투수성 지역에서 발생하는 비점 오염물질 항목별 단위면적당 오염부하량은 매우 높은 값 을 나타내고 있는데, 이는 불투수성 지역의 특성상 아스 팔트로 되어 있는 도로 및 주차장, 교량 등이 있는 불투 수면이 대부분의 토양상부를 덮고 있기 때문에 강우시 불 투수성 지역 내 모니터링 지점에서 강우가 집중되어 유 출되기 때문에 비점오염물질의 유출이 증가하기 때문에 오염부하량이 증가한 것으로 판단된다. 강우시 초기세척 효과는 TSS의 경우, Event 1, Event 2에서 초기세척효과 가 매우 잘 관찰되었으며, TSS¤CODMn¤T-P 순으로 뚜 렷하게 나타나는 것으로 조사되었다. TSS와 CODMn가 가 장 민감하게 강우에 영향을 받는 것으로 나타났다. 이에 본 연구 결과를 통해 분석된 결과를 토대로 비점오염원 유출특성에 대한 다양한 데이터베이스를 구축하여 향후 비점오염원을 효율적으로 관리하는데 자료로 활용 가능 할 것으로 판단된다. 또한 비점오염원을 체계적으로 관리 하여 수계환경의 오염부하를 줄일 수 있는 방안을 강구 해야 할 것으로 사료된다.
Information on time spent in microenvironments has a critical role in individuals’ exposure assessment. Time-activity studies have become an integral part of comprehensive exposure assessment and personal exposure modeling. The aims of this study were to estimate the exposure level of NO2, PM10 and VOCs, and to compare the estimated exposure by using time-activity pattern and indoor air concentration. This study was performed upon 28 university students living in Daegu. We measured air pollutants of NO2, PM10 and VOCs at houses where the university students spent most their times. In this study, according to the summer and winter, time-activity patterns of university students were different. The 28 university students average spending times in house indoors and other indoors time were 11.52±2.14 and 7.63±2.65 hours in summer, and 14.78±3.30 and 6.59±3.03 hours in winter, respectively. The university students personal exposure NO2 concentrations were average 21.62±5.88 ppb and I/O ratio was 0.89±0.27. Personal average exposure of PM10 concentration was between house indoors and outdoors concentrations which indoor house concentration was 37.68±7.57 μg/m3 and outdoor house concentration was 43.85±9.80 μg/m3 with 0.88±0.17 of I/O ratio. Personal exposure to benzene and the average concentration of benzene did not exceed in atmosphere environmental standard (annual 1.5 ppb) and the outdoor houses concentration was much higher than indoor houses.
The aim of this study was to compare the concentrations of airborne pollutants (i.e., PMs, TVOC, and ozone) released from a laser printer with a new and/or a refilled toner cartridge. Also we compared the concentrations before and after attaching a HEPA filter at the outlet of exhausted air for each printer. PMs, TVOC, and ozone were released from all three different branded printers with both toner cartridges in accordance with their both a brand new and a used condition. For PMs, there were generally significant differences of concentrations between a brand new and used toner (p<0.05). Ozone level differences were found between a new and a refilled toner, but were not significant (p>0.05). For TVOC, there were significant differences of concentrations among brands, and toluene (3.46mg/m3) only was identified. The overall 70% of reduction for PMs’concentrations occurred after attaching a HEPA filter(p<0.05), and these results were pronounced for TSP. These results showed that similar levels of airborne pollutants were released from a laser printer with a new and a refilled toner cartridge. Also, these results indicate that the usage of a HEPA filter may be an effective method for reducing the released pollutants from a laser printer.
Odorous compounds were monitored and dispersion modeling was conducted using AERMOD model. for Songtan Industrial Complex (SIC) located in Mogok-dong, Pyeongtaek city. The complex odor at the target area showed an average dilution ratio of 4.5 and low ammonia concentrations were observed (78.3 ppb). Sulfide, methyl iso-buthyl ketone, methyl ethyl ketone and styrene were not detected. The toluene concentration showed as 1233.3 ppb, which was the highest in the target compounds. The diffusion effect of odorous pollutants by wind was confirmed by descending order of concentration, inner-SIC (282 ppb) > downwind site (182 ppb) > upwind site (11.6 ppb). The results of the modeling demonstrated that the complex odors on the west and, south, north and east of the boundaries were dilution ratios of 10 24 and 20, respectively indicating the north and the east of SIC were more vulnerable to odor pollution than other regions.
This study aims to provide preliminary review for standardization of methods for evaluating reduction performance of pollution-reducing building materials and to select commercially available pollution-reducing building materials for assessing their current status. The ISO 16000-23 and -24 standards were used as references for standardizing the test methods. The sub test categories—stability of the supply air concentration, type of the supply air, and supply air concentration—which were not included in the standards were selected and conducted for the purpose of this study. Five (5) wall materials and 2 ceiling materials were tested for formaldehyde reduction performance and 3 wall materials were tested for toluene reduction performance. The study included experimental review of the essential test criteria such as stability of the supply air, internal stability of the chamber, and recovery rate. The samples tested exhibited some reduction performance for formaldehyde but little reduction performance for toluene.