• 한국환경보건학회지
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• 제33권2호
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• pp.145-149
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• 2007

The range of reduction rates of airborne bacteria concentration at 6 hrs, 12 hrs, 24 hrs and 48 hrs, which means a storage time until input of agar media into incubator after air sampling with an impactor. were 15-20%, 25-40%, 35-50% and 55-70%, respectively, compared to initial concentration. Types of agar media and storage thermal condition did not significantly affect a collection efficiency of impactor in terms of evaluating airborne bacteria level (p>0.05). To better improve the impactor's collection efficiency of airborne bacteria, based on the result of this study, it is recommended that the vicinity of $25^{\circ}C$ should be sustained until input of agar media into incubator after air sampling.

• 한국입자에어로졸학회지
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• 제12권4호
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• pp.151-159
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• 2016

Since airborne viruses have been known to aggravate indoor air quality, studies on development of anti-viral air filter increase recently. In this study, a mass aerosol particle generator for coating a commercial air filter (over $300{\times}300mm^2$) was built, and evaluated by comparing a commercial particle generator. Then, via this device, a commercial air filter was coated with anti-viral material ($SiO_2-Ag$ nanoparticles in this study), so fabrication of commercial anti-viral air filter was performed and the pressure drop, filtration efficiency, and anti-viral ability of the filter were evaluated against aerosolized bacteriophage MS2 in a continuous air flow condition. The result showed that the particle generation of the new generator was more than about 8.5 times over which of the commercial one. Consequently, $SiO_2-Ag$ particle coating on a filter does not have significant effects on the filtration efficiency and pressure drop with different areas, and the average anti-viral efficiency of the $SiO_2-Ag$ filter was about 92% when the coating areal density was $1.0{\times}10^{12}particles/m^2$.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.442-447
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• 2006

In semiconductor manufacturing clean rooms, it becomes important to remove airborne molecular contaminants as well as particulate contaminant in outdoor air introduced into clean rooms. One suitable control technique for these chemical contaminants is air washing by water in an outdoor air handling unit. In order to enhance the removal efficiency of chemical contaminants the effect of adding a heating and humidifying process before an air washer was examined.

• 한국입자에어로졸학회지
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• 제15권4호
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• pp.173-182
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• 2019

Since airborne viruses have been known to aggravate indoor air quality, studies on the development of anti-viral air filter increase recently. In this study, the pressure drop and anti-viral efficiency of TiO₂ coated ceramic ball filter were evaluated. After the filter being inserted into a commercial room air cleaner, chamber test with aerosolized bacteriophage MS2 was performed. The porosity of TiO₂ coated ceramic ball filter was 0.85, and pressure drop was about 13 Pa for 1 m/s of air velocity. The anti-viral efficiency was about 93% when the reaction time was 25 minutes in a 1 ㎥ chamber.

• 한국입자에어로졸학회지
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• 제19권1호
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• pp.1-11
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• 2023

Respiratory face masks are protective facepieces that are designed to filter inhaled air. They are easy-to-use devices that can protect the wearer against various hazardous particles in the air. Respiratory face masks also prevent the spread of viruses and bacteria-containing droplets that are released from the coughing or sneezing of the infected people. During the COVID-19 pandemic, various types of face masks have circulated on the market. Their ability to filter sub-micron particles, which are the sizes of harmful particulate matter and airborne viruses, needs to be investigated. Their breathability, the easiness of breath through the mask, also needs to be considered. In this study, wwe evaluated the performance of filters used for different types of face masks certified by different standards including Korean (KF94, KF80, KF-AD), USA (N95), and Chinese (KN95) standards. We also tested the filters of nanofiber masks and surgical masks for which there are no standards for filtration test. The N95 mask filters showed the highest quality factor for capturing virus-sized particles. The other types of mask filters have acceptable performance except for nanofiber mask filters whose performance is very low.

• 한국환경보건학회지
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• 제32권1호
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• pp.36-45
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• 2006

The aim of this study is to examine size-based concentration and genera of airborne fungi distributed in public facilities such as hospital, kindergarten, day-care center and postpartum nurse center and to provide fundamental data in order to prevent respiratory diseases caused by exposure to airborne fungi. Culturable total and respirable concentrations of airborne fungi averaged to $382\;cfu/m^3\;and\;292\;cfu/m^3$ in hospital, $536\;cfu/m^3\;and\;347\;cfu/m^3$ in kindergarten, $334\;cfu/m^3\;and\;266\;cfu/m^3$ in day-care center, and $371\;cfu/m^3\;and\;289\;cfu/m^3$ in postpartum nurse center, respectively. The ratio of respirable to total concentration of airborne fungi in the investigated public facilities was ranged from $55\%\;to\;70\%$ but there was no significant difference among them (p>0.05). The mean I/O ratio of culturable total and respirable concentrations were 0.56 and 0.64 in hospital, 0.72 and 0.91 in kindergarten, 0.33 and 0.45 in day-care center, and 0.63 and 0.73 in postpartum nurse center, respectively. Indoor concentration of airborne fungi did not correlated significantly with indoor temperature and relative humidity (p>0.05) but had a significant positive correlation with $CO_2$ concentration (p<0.01) and surrounding condition (p<0.05). Penicillium spp., Cladosporium spp., and Aspergillus spp. were estimated to over $95\%$ of total airborne fungi identified in the investigated public facilities.

• 한국환경과학회지
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• 제11권7호
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• pp.669-677
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• 2002

This study was conducted to investigate the characteristics of role of transport on aerosol concentration at Crate Lake, Oregon USA for 1988.3~1999. 5. The IMPROVE program is a cooperative measurement effort governed by a steering committee composed of representatives from USA federal and regional-state organizations. Also IMPROVE sampler is designed to obtain a complete signature of the composition of the airborne particles affecting visibility. According to 10-day backward isentropic trajectory analysis, the frequency of local, marine and Asian trajectory showed 33.1%(335 cases), 47%(478 cases), 5.2%(53 cases) respectively. The monthly variation of nss $SO_4^{2-}$, nss S, $NO_3^-$, K and C showed the double peak pattern, high in April~May and August~september and showed the lowest concentration in Winter. The other constituents concentration except for Cl$^{[-10]}$ , Na, Mg was high in local trajectory than marine trajectory. A ratio nss $SO_4^{2-}$ to $SO_4^{2-}$ was 90.5% in marine trajectory and 98% in local trajectory. It suggest that the aerosol in Crater Lake was effected by salt. The annual mean concentration of nss $SO_4^{2-}$ and nss S decreased but the springtime concentration increased.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2005년도 국제학술대회
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• pp.273-278
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• 2005

This study was performed to investigate the characteristics of distribution for airborne bio aerosol in 11 public facilities in Seoul from June to July. The collected samples are total suspended bacteria in indoor and outdoor Anderson six stage air sampler by the IAQ standard method of Ministry of Environment in Korea. The concentration of total suspended bacteria in the theater higher than IAQ standards. As the results of the survey, the most high indoor air mean concentration of bacteria $1273CFU/m^3$ was theater and the most high outdoor air mean concentration of bacteria $^229 CFU/m3$was Kindergarten. The mean concentration of bacteria in the theater was higher than the IAQ standards established by the Ministry of Environment, Republic of Korea. Moreover, this study was for investigation a part of indoor air pollution condition in public facilities. It means that this study can't represent fDr all of public facilities. Therefore, we suggest that long and middle term country plan for management of IAQ should be established through long-term and continuous investigation of IAQ condition. Also above consideration in mind, it is suggest that the research for source contribution of the results on these need further study.

• 한국입자에어로졸학회지
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• 제16권4호
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• pp.107-117
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• 2020

충청남도 대형사업장에서의 대기오염물질 배출이 미세먼지 농도에 미치는 영향에 대한 논란이 많다. 2019년 봄과 가을에 항공관측을 수행하여 충청남도 대형사업장 상공에서 대기오염물질 농도를 측정하였고, 이를 바탕으로 황산화물(SO2) 배출량을 산정하였다(하향식 배출량). 이를 사업장에서 제시한 배출량 자료(상향식 배출량)와 비교한 결과, 항공관측에 바탕을 둔 배출량이 더 많았다. 항공관측에 바탕을 둔 배출량은 석탄화력발전소는 1502.1 kg/hr, 제철소는 2805.5 kg/hr였다. 이는 사업장에서 밝힌 2019년 연평균 배출량보다 각각 2.5배와 2.0배 큰 값이다. 이와 같은 차이가 나는 원인을 규명하기 위해서는 관측에 바탕을 둔 하향식 배출량과 활동도에 바탕을 둔 기존의 상향식 배출량을 산정함에 있어서 보다 면밀한 검토와 개선이 필요하다. 하향식 배출량의 개선을 위해서는 관측 불확도를 줄이는 것이 중요하다. 불확도를 높이는 요소의 하나는 지상에서 항공기가 운행될 수 있는 최저 고도까지 관측을 하지 않은 것이다. 이러한 불확도를 줄이는 방법은 지상에서 관측을 수행하며, 더 나아가서는 지상과 항공기 관측 최저 고도 사이에서 드론 등의 방법을 통해 관측을 수행하는 것이다. 바람장 역시 관측 및 외삽과 내삽을 이용하여 평면 분포를 구하면 평면에 대한 적분을 이용하여 평면 전체의 플럭스를 구할 수 있어 불확도를 줄일 수 있을 것이다. 상향식 배출량의 정확도 개선을 위해서는 측정이 이루어지고 있는 굴뚝의 배출량 자료 정확도 개선과 함께, 관측이 이루어지고 있지 않은 배출구의 현황 파악이 필요하다.

• Architectural research
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• 제8권1호
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• pp.37-45
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• 2006

A fungal spore transportation model that accounts for the concentration of airborne indoor spores and the amount of spores deposited on interior surfaces has been developed by extending the current aerosol model. This model is intended to be used for a building with a mechanical ventilation system, and considers HVAC filter efficiency and ventilation rate. The model also includes a surface-cleaning efficiency and frequency that removes a portion of spores deposited on surfaces. The developed model predicts indoor fungal spore concentration and provides an indoor/outdoor ratio that may increase or decrease mold growth risks in real, in-use building cases. To get a more useful outcome from the model simulation, an uncertainty analysis has been conducted in a real building case. By including uncertainties associated with the parameters in the spore transportation model, the simulation results provide probable ranges of indoor concentration and indoor/outdoor ratio. This paper describes the uncertainty quantification of each parameter that is specific to fungal spores, and uncertainty propagation using an appropriate statistical technique. The outcome of the uncertainty analysis showed an agreement with the results from the field measurement with air sampling in a real building.