This study was undertaken to investigate whether HEPA filter-equipped air purifiers can remove aerosolized virus, whether the removed virus can re-scatter through the filter, and how long the removed virus keeps its infectivity in the filter. For this investigation, six HEPA filter-equipped air purifiers produced by different companies were tested against PhiX174 and MS2 phages aerosolized by nebulizers. For viral detection from the air, LB agar plates covered with Escherichia coli hosts and an Andersen air sampler were used, and from the surface, the swab method was used. Both the aerosolized PhiX174 and MS2 viruses absorbed by the HEPA filters in the air purifiers were not detected from the air through filters or the surface of the outlet of the air purifiers. During the operation of the air purifiers at medium mode, the infectious viral concentration of these viruses in the HEPA filters decreased to 0%~12.3% as the time period passed. These results regarding infectious viral concentration differences were assumed to be due to the different wind speed and air volume among the six air purifiers. Based on observations over 5 days, the infectious viral concentration of the PhiX174 phage was 8,600 times lower when the air purifier was operated than when it was not operated. Overall, our results demonstrate that HEPA filter-equipped air purifiers can efficiently remove the two aerosolized viruses and the removed viruses in the HEPA filter could not re-spread and maintain their infectivity.

Many air purifiers have been developed and released with increasing PM. In generally, the performance of air purifiers has been evaluated in the environment chamber by relevant standards. However, as there is a lack of information about air cleaning performance of air purifier in the living area, consumers have difficulty with product selection. In this study, five air purifiers were tested in apartments with different structures. In order to examine the effect of air purifiers, we assumed 3 cases such as inflow of pollutants from outdoors by ventilation, smoking patterns of residents, and cooking methods (e.g., frying fish). The evaluation results showed that the efficiency of air purifier products D and B of the 3-stage configuration (pre-filter + HEPA filter + activity carbon) was the best in most experiments. In the case of the ionizer type E product, the efficiency was very low and, at times, had increased the particulate matter indoors. Considering the cost-performance ratio, it is most reasonable to use an air purifier comprising a pre-filter and a HEPA filter without an additional configuration.

본 연구에서는 사용 후 폐기되는 정수기용 역삼투(Reverse Osmosis; RO)막 필터를 세정하여 새 필터의 수준으로 복원시키는 연구를 수행하였다. 화학적 세정액으로는 수산화나트륨, 중아황산나트륨, EDTA용액을 사용하였으며 마이크로버 블 발생 장치와 함께 in-situ의 방법으로 세정하였다. EDTA를 0.1%의 농도로 제조한 뒤 마이크로버블과 함께 사용하여 30분 세정하였을 때 가장 좋은 결과를 나타내었다. 이때 폐 필터와 세정 후 폐필터의 성능을 비교해 보았을 때 투과도는 19.9%, 회수율은 49.5%증가하였으며 NaCl 100 mg/L 용액에 대한 염제거율은 2.3% 감소되었는데, 이는 새 필터와 동등한 수준으로 회복이 되었다. 또한 전자현미경 분석을 이용하여 막 표면의 오염물의 제거를 육안으로 확인하였다. 이로써 전량 매립 또는 소각 되어지는 정수기용 폐 RO막 필터의 세정을 통하여 재사용이 가능할 것으로 판단된다.

실내 공기질 관리의 중요성이 대두되면서 쾌적한 실내환경에 도움을 주는 공기청정 기능과 습도 조절 기능을 동시에 갖춘 제습기와 공기청정기가 각광받고 있다. 하지만 오랜 기간 동안 공기정화제품을 사용하게 될 시에는 필터가 오염되어 본연의 기능을 상실하게 되는 것으로 알려져 있지만 이에 대한 구체적인 연구나 보고는 드문 편이다. 이에 본 연구에서는 가정과 사무실 등에서 사용한 공기정화제품을 수거하여 주요 부위별 미생물 오염도 및 주요 오염 미생물들을 분석하였다. 그 결과, 4 종류의 공기정화제품에서 오염도가 높은 부위는 필터부위, 물이 직접 닿는 부위 및 공기가 외부로부터 직접적으로 들어오는 입구부위 등에서 미생물학적 오염도가 가장 높았다. 하지만 공기정화제품은 사용하는 환경과 조건에 따라서 미생물학적 오염도 및 오염 미생물의 성상은 각각 다르게 나타났다. 하지만 이들 공기정화제품들에는 공통적으로 Staphylococcus sp., Micrococcus sp. 그리고 Bacillus sp.의 세균과 Cladosporium sp. 및 Penicillium sp.의 진균이 공통적으로 오염되어 있는 우점종인 것으로 분석되었다.

요즘 IoT (Internet of things)에 대한 기술개발은 사업 전반에 걸쳐 이루어지고 있으며, 이에 따른 Big Data 분석으로 다양한 제품과 서비스가 만들어 지고 있다. 정수기를 사용함에 있어 과연 소비자는 어떠한 형태로 사용하고 있을까? 또한 정수기를 구성하고 있는 부품들은 어떻게 동작하고 있을까? 이러한 사항들을 측정하고 실사용 데이터를 수집 분석하기 위해 패널을 구축했고 가정집과 다중이용시설에 대해 각각 1년간 측정 분석하여 정수기 사용 패턴을 모니터링 하였다. 본 연구는 사용자의 사용하는 시간대와 장소, 온도와 습도, 사용자 특성 (자녀연령, 직업, 연령대, 수입) 등에 따라 나타나는 패턴을 분석하였다.

A water purifiers for home-use has been popularly used as increasing distrust of the drinking tap water in views of safety. Besides, chlorination of drinking water can produce trihalomethanes known as a carcinogens. In general, a water purifier is known to remove risk factors such as infectious microorganisms, harmful chemicals and heavy metals. We compared the change of water components before and after purification by a water purifier and evaluated the results whether this purification system is reliable or not for safety of drinking water. The samples of water from 11 sites at the campus of Jeju National University were examined by physicochemical analyses, including concentration of sodium, potassium, chloride, residual chlorine, boron, nitrate nitrogen, sulfur, hexavalent chromium, copper, iron, aluminium, silicon, selenium, vanadium, manganese, molybdenum, nickel, arsenic, antimony, zinc, cadmium, lead, strontium. Microbiological analysis was performed by counting mesophilic bacterial colonies. Almost of all the physicochemical components after purification were shown to decrease tendency of their concentrations but not significantly differenty except that of residual chlorine. Mesophilic bacterial counts after purification were shown to increase when compared to those of tap water. All the tap water was met the acceptance of requirement of drinking water, but samples of the water after purification were failed (4 from 11). After draining generous amount of water from a purifier, bacterial counts were observed to show a decreased tendency. Bacterial colonies were not detected when the concentration of residual chlorine was higher than 0.2 ppm. Although seasonal factors and maintenance condition were not concerned in this study, higher bacterial counts in purified water could cause some problems in using water purifier for home-use. Considering the results obtained, regular maintenance and care including filter change and sterilizing the reservoir are absolutely required. A further study is required to examine where the bacteria are coming from.

Quality test for activated carbon(AC) filter used for drinking water purifier is now an obligatory test and the standard material for valid purifying amount in water purifier performance test has been changed from residual chlorine to chloroform according to the notice of Ministry of Environment in 2006. Therefore, this study aimed to compare the ingredients of AC filters by confirming chloroform removal rate of AC filter and conducting 4 adsorption tests (Iodine, methylene blue decolorization, phenol value, ABS value) for AC filters provided by manufacturers. With water pressure of 1 kgf/cm2, 1,500 liters of prepared inflow went through to check chloroform removal rate. As a result, product with removal rate of below 60% from all products. On the other hand, 4 adsorption tests were conducted for filters in the market and filters from manufacturers. None of the products satisfied all 4 tests. In particular, they showed great shortage to the standard in phenol value and ABS value test. However, manufacturers' filter showed much better performance than filters in the market. Also, the result of valid purifying amount test for each of five products of appropriate product and inappropriate product based on filter quality test showed average 4,440 liters for appropriate product and average 2,620 liters for inappropriate product. According to the result, it is shown that the filter with good adsorption also had good chloroform removal efficiency and adsorption efficiency. Therefore, it is expected that customers can screen good quality product through obligatory conduct of filter quality test. However, it is considered that complementation in system is required for future inspection.