This study was carried out to examine the concentration and distribution characteristics of total airborne bacteria (TAB) and airborne mold in non-regulated public-use facilities. The arithmetic mean (AM) of the TAB in all facilities was 356.5 ± 419.3 CFU/m3, and the geometric means (GM) was 157.8 CFU/m3, which did not exceed the standard value of 800 CFU/m3. The highest concentration was 637.3 ± 372.0 CFU/m3 (GM: 534.9 CFU/m3) in the underground shopping mall. The AM of airborne mold in all facilities was 448.2 ± 429.6 CFU/m3 (GM: 285.4 CFU/m3), which did not exceed the standard value of 500 CFU/m3, but was close to it. In particular, subway station (AM: 661.5 ± 441.2 CFU/m3, GM: 540.0 CFU/ m3), large-scale store (AM: 587.6 ± 683.2 CFU/m3, GM: 297.8 CFU/m3), and private educational institute (AM: 528.8 ± 379.6 CFU/m3, GM: 373.7 CFU/m3) exceeded the standard. Operational taxonomic unit of 16S rDNA and ITS2 rDNA region was analyzed to profile bacteria and mold component in the air of the public-use facilities. As a result, Pseudomonas and Morganella are the major bacterial groups. Regarding mold, Aspergillus, Candida, Malassezia, and Penicillium are the major groups. Component of each airborne bacterial and mold groups varied depending on the type of public-use facilities.

As modern society has emerged and developed, the subway has established itself as a representative means of transportation in the city due to its speed, accuracy, and accessibility. According to the Indoor Air Quality Management Act, underground stations have established and managed the maintenance and recommendation standards for PM10, PM2.5, CO2, CO, HCHO, NO2, Rn, VOCs However, th the standards for airborne mold has not been applied for subway stations even though management for the health effect of exposure to mold is necessay. In this study, the correlation with major contributing factors was analyzed by measuring the concentration of airborne molds in the indoor air of underground stations and through literature research. It was confirmed that there was a correlation between the concentration of airborne molds in subway stations and the major contributing factors. As a result of the analysis, it was found that the concentration of airborne molds became higher as the location of the platform became deeper underground, during periods of congestion, and especially in summer. There was no significant correlation with the year of construction. Our findings indicate that appropriate management measures should be devised in response to such contributing factors.

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.

Mold is one of the harmful biological pollutants in the indoor environment. To investigate how the contamination degree of mold existing in the indoor environment differs according to the characteristics of the house, the concentration of mold in the indoor air was investigated for the houses damaged by leakage or flooding. As a result of a survey of 20 houses located in Gyeonggi-do and Chungcheong-do, the concentration of mold in indoor air surprisingly exceeded more than two times the recommended indoor air quality standard of 500 CFU/m3 in all the houses investigated. The fungal concentration was high in houses with condensation and mold odors. As for the housing type, the pollution degree was higher in detached houses than in row houses. As for the type of water damage, mold contamination was higher in the leaky houses than in the flooded houses. The degree of mold concentration was 1,237 CFU/ m3 in the leaky houses. In terms of housing age, pollution was very high in houses over 20 years old. The occurrence of these measured mold concentrations was correlated at a significant level with respect to the properties of the house. This study shows that in the case of water damaged houses, careful management of mold contamination is required.

Mold grows more easily when humidity is higher in indoor spaces, and as such is found more often on wetted areas in housing such as walls, toilets, kitchens, and poorly managed spaces. However, there have been few studies that have specifically assessed the level of mold in the indoor spaces of water-damaged housing in the Republic of Korea. We investigated the levels of airborne mold according to the characteristics of water damage types and explored the correlation between the distribution of mold genera and the characteristics of households. Samplings were performed from January 2016 to June 2018 in 97 housing units with water leakage or condensation, or a history of flooding, and in 61 general housing units in the metropolitan and Busan area, respectively. Airborne mold was collected on MEA (Malt extract agar) at flow rate of 100 L/min for 1 min. After collection, the samples were incubated at 25oC for 120 hours. The cultured samples were counted and corrected using a positive hole conversion table. The samples were then analyzed by single colony culture, DNA extraction, gene amplification, and sequencing. By type of housing, concentrations of airborne mold were highest in flooded housing, followed by water-leaked or highly condensed housings, and then general housing. In more than 50% of water-damaged housing, the level of airborne mold exceeded the guideline of Korea's Ministry of Environment (500 CFU/m3). Of particular concern was the fact that the I/O ratio of water-damaged housing was greater than 1, which could indicate that mold damage may occur indoors. The distribution patterns of the fungal species were as follows: Penicillium spp., Cladosporium spp. (14%), Aspergillus spp. (13%) and Alternaria spp. (3%), but significant differences of their levels in indoor spaces were not found. Our findings indicate that high levels of mold damage were found in housing with water damage, and Aspergillus flavus and Penicillium brevicompactum were more dominant in housing with high water activity. Comprehensive management of flooded or water-damaged housing is necessary to reduce fungal exposure.

To obtain basic data on bioaerosols in the indoor environments of houses located adjacent to Gwangyang Iron Works, the concentration and diversity of indoor air molds were comparatively investigated in 33 houses in September of 2016 and 2017, respectively. In areas both adjacent to and nonadjacent to Gwangyang Iron Works, house temperature and humidity ranged from 24~28oC and 47~57%, respectively. Airborne mold concentration was higher in the houses located nonadjacent than in the ones adjacent to the iron works. Interestingly, the level of airborne mold concentration exceeded 500 CFU/m3 in all houses nonadjacent to the iron works. A total of 12 mold species including five pathogenic species were indentified from the investigation. Among the five pathogenic species, the causal agents of otomycosis, Alternaria alternata, Aspergillus fumigatus, and A. niger were present. Overall, Cladosporium cladosporioides was the dominant species. This is the first report on the concentration and diversity of airborne mold in houses located adjacent and nonadjacent to Gwangyang bay industrial complex in Korea.