Passengers on public buses operating in the metropolitan area are exposed to the closed indoor air for minutes to hours. The indoor air quality of buses is mostly controlled through ceiling-mounted ventilation and filtration devices. A simulation study using a commercial code was conducted for fluid flow analysis to evaluate the potential effectiveness of an air purifier that can be inserted into bus windows to supply clean air from the outside to the inside. As a result of field measurements, the average CO2 concentration inside the bus during morning and evening rush hours ranged from 2,106±309 ppm to 3,308 ± 255 ppm depending on the number of passengers on board. This exceeded the Guideline for Public Transportation. The optimal installation position of an air purifier appeared to be the front side of the bus. In fact, even a low diffusing flow velocity of 0.5m/s was effective enough to maintain a low concentration of CO2 throughout the indoor space. Based on numerical analysis predictions with 45 passengers on board, the maximum CO2 concentration in the breathing zone was 2,203 ppm with the operation of an air purifier.

Vulnerable populations in healthcare facilities are more sensitive to exposure to indoor air pollutants, and therefore are more affected by such pollutants than the general population. This was the underlying reason why studies of indoor air pollutant concentration distribution and health risk assessment have been conducted targeting facilities, such as daycare centers, medical facilities, elderly care facilities, and postnatal care centers. However, previous studies have mainly focused on daycare and medical facilities for their research, and relatively speaking, studies conducted on the other venues are lacking. Therefore, this study aims to present the current status of indoor air quality and perform a health risk assessment in regard to Formaldehyde exposure at postnatal care centers and elderly care facilities. Here, the study focused on facilities that had undergone pollution level inspections from January 2017 to December 2021. A total of 81 postnatal care centers and 48 elderly care facilities were selected as the subject of the study. Then, the study utilized concentrations of five elements (CO2, HCHO, PM10, PM2.5, TBC) to determine the status of indoor air quality of both postnatal care centers and elderly care facilities. For health risk assessment, HCHO concentration was used. The investigation demonstrated that the yearly average concentration of the five elements stood within the indoor air quality maintenance standards, and the ratio of PM2.5 to PM10 in the two types of facilities was distributed as high as about 70%. In addition, the study showed that HCHO and TBC demonstrated a positive correlation when the relationship between indoor temperature and humidity with the five elements was examined. The health risk assessment showed that the cancer risk level of postnatal care center users stood below 10-6, below the level that is perceived as an acceptable risk. The cancer risk of workers from both postnatal care centers and elderly care facilities and elderly care facility users exceeded the acceptable risk level of 10-6, but was shown to be below 10-4, the maximum acceptable risk.

Fungi are organisms that must be monitored and controlled in order to preserve valuable paper records. They reduce the quality of paper records by degradation and/or discoloration. As an effort to understand fungal contamination in the National Archives of Korea, the concentration of fungi in the indoor air of the unsterilized record rooms has been reported. However, what species are present in the facilities is not much known. In the present study, we examined the fungi isolated from the National Archives of Korea and found among them that there are fungal species which are newly documented in Korea. They were identified based on morphological properties and nucleotide sequences analysis of the polymerase chain reaction-amplified the internal transcribed spacer region of rDNA, calmodulin gene, and beta-tubulin gene. We report Cladosporium parahalotolerans, Cladosporium subuliforme, Ochroconis mirabilis, Penicillium angulare, and Penicillium fundyense as new instances of fungal species in Korea. Among these five species, P. angulare is known to able to produce cellulase and O. mirabilis as an opportunistic pathogen of human and animals.

This study measured the suspended fungal concentration in indoor multiple facilities nationwide. The regions were selected as representative cities by region: Seoul, Gyeonggi (Incheon), Gangwon, Gwangju, Daejeon, and Busan. A total of 2028 regional comparisons, including department stores, schools, public toilets, libraries, and banks, subway, sports facilities and comparative analysis were conducted for each multi-use facility industry. Among the nationwide, Among the regions, the average concentration of floating mold in indoor multi-use facilities was the lowest in Busan at 394.67 CFU/m3, followed by Gyeonggi and Incheon 487.90 CFU/m3, Seoul 542.84 CFU/m3, Daejeon 809.30 CFU/m3, Gangwon 1,145.22 CFU/m3, Gwangju was 1,371.10 CFU/m3 in the order. Busan was the lowest, and Gangwon was the highest. The reason that Busan, which has a high average temperature and population density, shows a lower mold concentration than Gangwon, is that floating mold in the indoor air is not affected by the external atmospheric environment, population density, and number of facility users. Although it cannot be said that there is no influence of the atmospheric environment, it was found that the indoor environment has different characteristics from the outdoor environment. The importance of air quality management has been confirmed, and further, it is necessary to subdivide the management standards by region and multi-use facilities, and the management standards need to be converted to maintenance rather than recommendations.

Air curtains, blowing air streams across a doorway, were installed in trial trains on subway line 7 in 2021 and they have been operated with dust collectors to improve the air quality of subway trains. In this study, we investigated the effects of air curtains on the indoor air quality in the trial subway trains. The concentrations of PM2.5 and carbon dioxide in the four selected cabins were measured in the morning hours (e.g., 7:30–11:30 am including the morning rush hour). The measurements were conducted on February 26, March 31, April 30, and May 14, 2021 and air curtain (AC)s and dust collector (DC)s in the four cabins were operated differently on those measuring days. All devices were turned off in the control cabin and only ACs, only DCs, and both the ACs and DCs were turned on in the other three cabins, respectively. The 4-h-averaged PM2.5 concentrations in the cabins, where only ACs and only DCs are turned on, are lower than in the control cabin by 18% and 26%, respectively. In addition, the joint operation of ACs and DCs can decrease the PM2.5 concentration by up to 42%. The time series of PM2.5 concentrations, measured on April 30, illustrate again that ACs block the intrusion of outside particulate matters. The 4-h-averaged carbon dioxide concentrations in the four cabins do not show monotonic differences between the cabins because of the generation of carbon dioxides inside the cabins. When the weights of individual cars and thus the numbers of passengers are similar between the cabins, the carbon dioxide concentrations in the ACs-operated cabins are higher than in the control cabin. This indicates that ACs can block the outward emission of carbon dioxides and maybe other indoor air pollutants as well.

Fungi have been known as an irritant or causal agent of asthma. Thus, information on their concentration and diversity in indoor air of asthmatic patient’s houses is valuable for the management of these micro-organisms. The present study was performed to investigate fungal concentration and diversity in indoor air of resident spaces in two adult patient’s houses in winter. Air samples were collected in February of 2018 from living rooms and bedrooms of two asthma patients’ houses located in two different places in Incheon city using an impaction method. The average concentrations of airborne fungi did not exceed the 500 CFU/m3 level which is recommended by the Enforcement Managements of the Indoor Air Quality, Ministry of Environment, Korea. A total of four genera and 23 species were identified based on morphological and molecular methods. Aspergillus and Penicillium were two major genera. Aspergillus pseudoglaucus and Penicillium citrinum were commonly found between the two patient’s houses. Among the identified fungi, three species, Aspergillus venenatus, Penicillium jamesonlandense, and Penicillium salami were found to be unrecorded species in Korea. The morphological and molecular characteristics of these three unrecorded species were described. Since these species produce spores well and a lot, they are considered to be a species that needs management. This study provides basic information on the fungi for indoor air quality management in the living spaces of asthma patients in winter in Korea.

Indoor air quality management is essential for a healthy life. However, it is difficult to perceive, detect, and monitor the level of indoor air pollution and this means that it is possible to be exposed to more pollution indoors than outdoors. In this study, in order to derive effective indoor air quality management measures, public perceptions and behavioral characteristics regarding indoor particulate matter and air quality management methods were investigated through a survey of 1,000 people. Based on the survey, it was found that most of the respondents had a negative perception of the indoor air quality of their residence, and natural ventilation was the most used method for indoor air quality management. Although the frequency of use of air quality management devices such as air purifiers and mechanical ventilation systems was relatively low, their effect regarding air quality management was positively perceived. In particular, the results of survey indicated that respondents of families which included members with fragile health engaged in more active behavior regarding in indoor air quality management than those respondents whose family members had no health issues and that the former have used air quality management devices more frequently. Therefore, it is necessary to develop proper guidelines to encourage more people to actively participate in improving indoor air quality.

Airborne bacteria are expected to float in the mushroom cultivation house, as it is a special environment with high humidity and high temperatures. Their concentration and diversity in the indoor air of the cultivation house could effect the health of farmers and the quality of mushrooms. To examine whether microbiota of airborne bacteria change from year to year, we measured the indoor temperature, humidity, and airborne bacterial concentration from mushroom cultivation houses located in six regions in Korea from 2020 to 2021, and isolated and identified airborne bacteria. The surveyed data were compared and the bacterial diversity of the 1st year and the 2nd year were determined. Based on the average temperature and humidity data surveyed, it can be seen that the temperature and humidity environment in the cultivation houses is such that bacteria can easily reproduce. It was observed that the temperature inside the cultivation houses tends to be higher or lower depending on the season and correlates with the temperature outside the cultivation houses. In the first year survey, 32 species of 20 genera were identified, and in the second year survey, bacteria belonging to 29 species of 22 genera were identified. Among them, the most detected species were all species belonging to the genus Bacillus. There were only three species (Bacillus altitudinis, Brevibacterium frigoritolerans, and Staphylococcus epidermidis) that were continuously isolated in common. Our results showed that the species of floating bacteria greatly vary from year to year even for the same cultivation houses.

In this study, indoor air quality indices (IAQI-C and IAQI-E) were developed for child care centers and elderly care centers based on health effects, and compared to the air quality index (CAI) for outdoor atmosphere. In addition, composite indices that integrate individual indices for each pollutant were developed to quickly and conveniently recognize the current air quality. Among all data, 71.2% and 35.6% belonged to the grades 'Good' and 'Moderate' for child care centers and elderly care centers, respectively. This assessment is more stringent than the CAI's criteria.

본 연구에서는 보육시설 실내공기에서 분리된 식중독 균 주의 독소 유전자 분포와 항생제 내성을 분석하여 보육시설 실내공기에 의한 식중독 발생을 사전 예방하고 식중독 발생 시 적절한 치료를 위한 기초자료를 제공하고자 하였다. 어린이집 실내공기에서 분리된 Staphylococcus aureus 16주, Bacillus cereus 37주를 실험대상으로 하였다. S. aureus와 B. cereus 독소 유전자는 PCR 방법으로 검출하였다. 항생제 감수성 실험은 Clinical and Laboratory Standard Institute의 디스크 확산법에 따라 실험하였다. S. aureus 16 균주 중 11 균주(68.6%)에서 seg와 sei 독소 유전자가 검출되었다. B. cereus 37 균주 모두에서 nheA와 nheB 독소 유전자가 검출되었다. B. cereus 독소 유전자 패턴은 총 12개로 나타났으며 nheA-nheB-nheC 독소 유전 자가 가장 중요한 패턴으로 나타났다. S. aureus 16 균주의 항생제 감수성실험 결과 ampicillin과 penicillin 항생제 에 93.8%, 87.5% 내성을 나타내었으나 methicillin resistance Staphylococcus aureus와 vacomycin resistance Staphylococcus aureus는 검출되지 않았다. B. cereus 37 균주의 항생제 감수성 실험 결과 ampicillin과 penicillin 항생제에 100% 내성을 나타냈었다. 이러한 결과를 종합하여 볼 때 보육시 설 실내공기에 오염된 S. aureus와 B. cereus에 의한 식중독을 발생을 예방하기 위하여 주기적인 환기와 공기 질 관리가 필요한 것으로 판단되었다.

In order for records to be preserved for a long time without physical and chemical transformation, the preservation environment of the library is very important, and environmental problems must be improved through periodic investigation on the preservation environment. Against this background, this study derived fine dust (PM10) and ultrafine dust (PM2.5) concentration data for the libraries, hallways, and workrooms of the National Archives of Korea over two years. There was a difference in the concentration of fine dust and ultrafine dust among facilities, and there was a change in the concentration depending on the month. Both fine dust and ultrafine dust concentrations were present at less than 10 μg/m³ in the libraries. In the hallways, both fine and ultrafine dust concentrations were highest in July. In the workplaces, the monthly fluctuations in the concentration of fine dust and ultrafine dust were large. And the concentration of fine dust and ultrafine dust in the workplaces were higher than those in the library and hallways. Overall, the concentration of fine dust and ultra-fine dust was measured below the maintenance standards stipulated by the Indoor Air Quality Management Act of the Ministry of Environment of Korea in all the investigated facilities. The results of this study are expected to be used as fundamental information to manage the indoor air quality of the facilities of the National Archives.

Temperature, humidity, and fungal concentration were investigated during the period from May 2019 to August 2021 to obtain information on the indoor air quality in the facilities of the National Archive of Koea, located at Seongnam, Daejeon, and Busan, respectively. The temperature and humidity of the undisinfected libraries was properly maintained for the preservation of papepr records. The airborne fungal concentration differed among the libraries, changed according to the season, and increased especially between June and August. Similarily, the concentration of airborne fungi in the hallways adjacent to the libraries also fluctuated depending on the season and showed a tendency to rise in the months when the ourside temperature rose. In general, the concentration of airborne fungi in the hallways was somewhat higher than that of the libraries. Importantly, it was identified that the concentration of airborne fungi exceeded the recommended standard (500 CFU/m3) by the Ministry of Environment of Korea only in the workroom where the classification and condition inspection of undisinfected records imported from outside were performed. Investigation of airborne fungal concentration from May 2021 to August 2021 showed that the 24 undisinfected libraries in Seongnam, Daejeon, and Busan were all good at 100 CFU/m3 or less. The results of this study are expected to be used as basic data to manage the indoor environment of facilities in the National Archives.

This study was conducted to help manage total floating bacteria and fungi in the indoor air by studying the characteristics of total floating bacteria and fungi according to the indoor CO2 concentration of daycare centers. The sampling and analysis of samples was based on the indoor air quality process test method, and the result analysis was conducted using the SPSS statistical program to perform correlation and regression analysis. Correlation and regression results show that CO2 and total airborne bacteria showed positive relationships, but airborne mold did not show relevance. In addition, in order to identify factors affecting airborne mold, correlation analysis and regression analysis were performed regarding total airborne bacteria, PM10, PM2.5, HCHO, outdoor mold, I/O ratio, indoor temperature/ humidity, area per classroom and volume. The results showed that the factors affecting airborne mold were I/O ratio, outdoor airborne mold, and total airborne bacteria. Research results show that CO2 and total airborne bacteria can be reduced and controlled by natural ventilation, and in the case of airborne mold, mechanical forced ventilation such as hoods will be necessary due to the introduction of outdoor airborne mold. In addition, it is necessary to consider I/O ratio criteria in order to confirm effective indoor mold contamination, taking into account the effect of outdoor mold inflow.

In this paper, a survey on students’ perceptions of air pollution, particulate matter (PM) and indoor air quality (IAQ) in school classrooms was analyzed. A total of 174 students participated in the survey, where 127 and 47 participants were elementary school students and middle school students, respectively. The elementary school was located in a rural area of Korea, whereas the middle school was located in an urban area. The questionnaire of the survey was mainly composed of three parts: (1) students’ perceptions of air pollution, (2) students’ perceptions of IAQ in the classroom, and (3) students’ perceptions of how to improve IAQ in the classroom. Based on our study, the responses of the students for the given questionnaire showed an opposite tendency. The students in the rural area tended to have positive perceptions regarding IAQ in the classroom as well as air pollution, whereas the students in the urban area revealed negative perceptions for the same items. Our survey results can be used by school officials in order to maintain and improve IAQ in school classrooms based on the perceptions of the students.

National concerns about air pollution are growing. The importance of indoor air quality is emerging because people live in an indoor environment more than 90% of the day. In particular, the indoor air quality of schools needs to be managed as teenagers are vulnerable to environmental pollution. The government has designated the School Health Act in order to manage indoor air quality in schools. Air purifiers have been operated to improve indoor air quality in the classroom since 2018. In this study, we performed on-site evaluations in some classrooms, and then we proposed a plan for improving the air quality in the classroom. In this study, PM10, PM2.5, and CO2 in classrooms in Chungnam were measured to analyze the effect of air cleaner supply. A portable aerosol spectrometer (PAS, model 1.109, Grimm) and CO2 meter (TES 1370, TES) were used as measuring instruments. Schools A and B exceeded the recommended standards, while school C met the standards. The ratio of PM10, PM2.5 in classrooms A and B was 0.58 and 0.5, respectively. Correlation analysis was performed between indoor and outdoor pollutants to analyze the effects of particulate pollutants present in each classroom. First, the measured concentration of fine particles was classified according to/on the basis of factors that affect/influence the internal environment of the classroom. Then, fine dust concentrations measured at the same time as AQMS were classified with regard to the external factors. The gradients for each classroom were 1.57, 1.63, and 1.54, although there were differences in concentration, but they were relatively similar. It is necessary to develop and disseminate customized air purifiers considering the activity of the occupants of classrooms. It is important to consider the areas in which s tudents breathe when installing air purifiers in the classroom. In addition, follow-up management of air purifiers is an essential element. For efficient operation and management of indoor air quality, it is necessary to develop and disseminate standard manuals for air purifiers. It is proposed that an environmental manager should be deployed in schools to manage environmental issues. Standardization of air purifiers, management guidelines for standard manuals, and field support for environmental sheriffs should be established on a legal basis.

This study aimed to assess the pollution level in 13 crowded subway stations in an effort to understand the spatial and seasonal factors of Indoor Air Quality. The main measured items were particulate pollutants such as PM10 and PM2.5 and gaseous pollutants such as CO2, HCHO, Rn, TVOC, BTEX, and Styrene at concourses and platforms in the summer and winter periods. The influence of the draught created by the movement of the train was classified into lateral and island platforms, and the concentrations of PM by location (entrance, middle, and end) were statistically compared and analyzed. As a result, the concentrations of PM were confirmed high in the order of Platform > Concourse > Ambient air. In particular, in the case of platform PM10, the frequency exceeding the standard value (100 μg/m3) was 38.5% and the maximum concentration was 196.2 μg/m3. All gaseous pollutants were at lower levels than the standard, and the factors affecting CO2 and Rn were identified as the number of users and geological characteristics, respectively. The principal component analysis (PCA) demonstrated that PM was found to be a major indicator of the air quality management of subway stations. In particular, the concentrations at entrance and end areas in the lateral platform were about 1.4 times higher with regard to PM10 than in the middle area, and about 1.9 times higher with regard to PM2.5 due to the effect created by the draught produced by the movement of the train. Therefore, in order to manage PM in the platform area, a specialized management plan for places with particularly high PM concentration within the platform area is required. In addition, it is necessary to evaluate the effect created by the draught produced by train movement when selecting locations for measuring indoor air quality.