Young children health problem were reported in a Korean daycare centers and supposedly attributed to the presence of air pollutants. This study attempted to characteristics of carbonyl compounds exposure of young children at the indoor spaces. The characteristics associated with the major indoor pollutants exposure included seasonal variation, and room location inside a daycare centers. As the results of investigation for daycare centers, the mean concentrations of formaldehyde, acetone, and acetaldehyde in daycare centers were 38.3㎍/m3, 33.9㎍/m3, 13.6㎍/m3, respectively. The indoor space carbonyl compounds concentrations were both higher for the summer than for the other seasons. The temperature and relative humidity measured along with the volatile organics measurements temperature and relative humidity increase volatile organics levels. This last suggestion is further supported by the correlations of the carbonyl compounds measured for daycare centers. Significant correlations between carbonyl compounds were exhibited for both the temperature and humidity, with at least p<0.05. The concentrations of formaldehyde in classroom were higher than lobby or dining room. Therefore, controlling indoor air pollutants exposure in daycare center should be given a high priority so as to minimize the potential sources of air pollutants in indoor space.

Present study evaluated the low-temperature destruction of n-hexane and benzene using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst. The parameters tested for the evaluation of catalytic destruction efficiencies of the two volatile organic compounds(VOC) included input concentration, reaction time, reaction temperature, and surface area of catalyst. It was found that the input concentration affected the destruction efficiencies of n-hexane and benzene, but that this input-concentration effect depended upon VOC type. The destruction efficiencies increased as the reaction time increased, but they were similar between two reaction times for benzene(50 and 60 sec), thereby suggesting that high temperatures are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Similar to the effects of the input concentration on destruction efficiency of VOCs, the reaction temperature influenced the destruction efficiencies of n-hexane and benzene, but this temperature effect depended upon VOC type. As expected, the destruction efficiencies of n-hexane increased as the surface area of catalyst, but for benzene, the increase rate was not significant, thereby suggesting that similar to the effects of the reaction temperature on destruction efficiency of VOCs, high catalyst surface areas are not always proper for economical thermal destruction of VOCs. Depending upon the inlet concentrations and reaction temperatures, almost 100% of both n-hexane and benzene could be destructed. The current results also suggested that when applying the mesh type transition Metal Pt/SS catalyst for the better catalytic pyrolysis of VOC, VOC type should be considered, along with reaction temperature, surface area of catalyst, reaction time and input concentration.

This study evaluated the technical feasibility of the application of TiO2 photocatalysis for the removal of volatile hydrocarbons(VHC) at low ppb concentrations commonly associated with non-occupational indoor air quality issues. A series of experiments was conducted to evaluate five parameters (relative humidity (RH), hydraulic diameter (HD), feeding type (FT) of VHC, photocatalytic oxidation (PCO) reactor material (RM), and inlet port size (IPS) of PCO reactor) for the PCO destruction efficiencies of the selected target VHC. None of the target VHC presented significant dependence on the RH, which are inconsistent with a certain previous study that reported that under conditions of low humidity and a ppm toluene inlet level, there was a drop in the PCO efficiency with decreasing humidity. However, it is noted that the four parameters (HD, RM, FT and IPS) should be considered for better VHC removal efficiencies for the application of TiO2 photocatalytic technology for cleansing non-occupational indoor air. The PCO destruction of VHC at concentrations associated with non-occupational indoor air quality issues can be up to nearly 100%. The amount of CO generated during PCO were a negligible addition to the indoor CO levels. These abilities can make the PCO reactor an important tool in the effort to improve non-occupational indoor air quality.

Petroleum refineries have been considered as an important emission source for atmospheric volatile hazardous air pollutants(HAPs). The emission source includes petroleum refinery processes and process equipment. The control strategy for volatile HAPs requires emission estimations of these pollutants. However, systematic methods of volatile HAPs emission from petroleum refineries have not yet been established. Accordingly, present study surveyed the estimation method of volatile HAPs emitted from the petroleum refinery processes and process equipment. The emission estimation methods for the petroleum refinery processes are applied for 11 petroleum refining facilities: fluidized catalytic cracking, thermal cracking, moving bed catalytic cracking, compressed engine, blowdown system, vacuum distilled column condensator, natural gas or distilled boiler, natural gas or distilled heater, oil boiler, oil heater and flare. Four emission estimation methods applied for the petroleum refinery process equipment are as follows: average emission factor approach, screening ranges approach, EPA correlation approach and unit-specific correlation approach. The process equipment for which emission factors are available are valves, pump seals, connectors, flanges and open-ended lines.

Evaluated were household THMs exposure associated with the use of municipal tap water treated with chlorine and with ozone-chlorine. The current study measured the THMs concentrations in the tap water and indoor and outdoor air in the two types of household, along with an estimation of THMs exposure from water ingestion, showering, and the inhalation of indoor air. Chloroform was the most abundant THMs in all three media, yet no bromoform was detected in any sample. Contrary to previous findings, the fall water THMs concentrations exhibited no significant difference between the chlorine and ozone-chlorine treated water. However, the spring median chloroform concentration in the tap water treated with chlorine (17.6 ppb) was 1.3 times higher than that in the tap water treated with ozone-chlorine (13.4 ppb). It is suggested that the effects of the water parameters should be considered when evaluating the advantage of ozone-chlorine disinfection for THMs formation over chlorine disinfection. The indoor air THMs concentration trend was also consistent with the water concentration trend, yet the outdoor air THMs concentrations did not differ significantly between the two types of household. The indoor to outdoor air concentration ratios were comparable with previous studies. The THMs exposure estimates from water ingestion, showering, and the inhalation of indoor air suggested that, for the residents living in the surveyed households, their exposure to THMs in the home was mostly associated with their household water use, rather than the indoor air. The THMs exposure estimates from tap water ingestion were similar to those from showering.

체계적으로 분석된 대구지역의 PM10 오염도의 시간적 및 공간적 특성과 대조지역에서 측정된 PM10 오염도에 근거하여 대구지역의 PM10 오염에 대한 저감 방안이 다음과 같이 제시된다. 대구시의 지역특성에 따른 PM10 관리의 관점에서 볼 때 대구지역의 PM10 관리는 다른 지역보다는 도로변 또는 도로변 인근지역, 그리고 공업지역에서 우선적으로 이루어져야 하고 지역적으로 PM10 관리 전략을 달리하여야 함을 제시하고 있다. 남산동, 삼덕동 및 대명동을 포함하여 도로변 또는 도로변 인근의 주택에 거주하는 주민의 PM10으로부터 건강 위해성을 줄이기 위해서는 자동차 교통 관리가 가장 우선적으로 수행되어야 한다. 한편, 노원동과 중리동을 포함한 공업지역 또는 인근에 거주하는 주민의 PM10으로부터 건강 위해성을 줄이기 위해서는 자동차 교통 관리 보다는 공단 배출 PM10 관리가 가장 우선적으로 수행되어야 한다. 나아가, 본 연구결과에 기초할 때, 비록 만성영향과 밀접한 관련이 있는 평균농도는 모든 지역에서 PM10 대기환경 기준치 이하로 나타났지만, 급성영향과 밀접한 관련이 있는 최대 농도와 결코 낮지 않은 PM10 대기환경 기준치를 초과하는 빈도수를 고려할 때, 대구지역의 PM10 관리는 지속적으로 수행되어야 함이 강조된다. 대구지역의 시간대 별 PM10 관리 관점에서 볼 때, 대구의 일반 주거지역의 PM10 관리는 오전 10시에서 오후 1 3시에 집중되어야 효율적인 PM10 관리가 될 수 있음을 의미한다. 공업지역인 중리동과 노원동의 경우, 다소 이른 오전 7시부터 오후 1 2시 사이에 PM10 관리가 집중되어야 효율적인 PM10 관리가 될 수 있을 것이다. 반면에 상업/주거 지역인 삼덕동과 대명동 그리고 도로변 지역인 남산동의 경우, 특정 시간대가 아닌 거의 전 시간대에 걸쳐 PM10 관리해야 하고 특히 자동차 배출 PM10 관리대책 수립이 시급하다. 대구지역의 요일 별 PM10 관리 관점에서 볼 때, 모든 지역에 대하여 일요일과 월요일의 PM10 농도가 낮게 나타났으므로 화요일에서 토요일까지 집중되는 것이 PM10관리가 효율적으로 수행될 수 있음을 의미한다. 대구지역의 월 별 PM10 관리 관점에서 볼 때, 모든 지역에서 하절기인 7월, 8월 및 9월에 낮은 농도를 나타내었고, 동절기인 11월 2월 보다는 오히려 이른 봄인 3월에 최대 농도를 나타내고 있으므로 모든 지역에서 3월에는 특별한 PM10 관리가 이루어져야 하고, 특히 근본적인 문제점인 중국의 황사현상을 저감하기 위한 중국과의 외교적인 노력이 요구된다. 대구지역의 계절 별 PM10 관리 관점에서 볼 때, 계절적으로는 모든 지역에서 봄철에 가장 PM10 농도, 그 다음이 겨울, 가을 그리고 여름의 순으로 나타났다. 봄철의 가장 높은 PM10 농도와 여름철의 가장 낮은 PM10 농도는 앞의 월별 PM10 농도 변화에서도 설명된 바와 같이 각각 황사와 장마의 영향 때문인 것으로 사료된다. 여름과 가을 보다 높은 PM10 농도를 나타내는 겨울철의 경우, 난방 연료 사용의 증가로 인한 영향을 받는 것으로 사료되므로 청정연료 사용의 확대가 권장된다. 대부분의 경우, 대조지역에서 측정된 PM10 농도가 대구의 여섯 개 대기오염측정 지점에서 측정된 PM10 농도 보다 낮게 나타났고, 일부는 일반주거지역인 만촌동과 유사하게 나타났다. 따라서, 대구의 PM10 측정망 중에서 만촌동이 주위 PM10 오염원의 영향을 가장 적게 받는 주거지역임을 함께 고려할 때 대구시의 PM10 관리목표는 만촌동의 PM10 수준으로 유지함이 바람직한 것으로 제안된다.