Subway trains with air cleaners have been newly deployed in the Seoul Metro system. The purpose of this study was to determine differences regarding in-cabin particulate matter with respect to concentrations less than 10 um (PM10) and 2.5 um (PM2.5) through the operation of air cleaners in subway trains. One subway train newly installed with in-cabin air cleaners on Seoul Metro Line number 2 was chosen monitoring in 2020. In-cabin air cleaners were turned-on at both front and back areas while those in the middle area were turned-off while the train was running. In-cabin PM10 and PM2.5 concentrations were measured in each area using a real-time aerosol monitor. Average in-cabin PM10 concentrations were statistically significantly lower (by 15%) in areas with air cleaners turned-on (43.8±12.1 μg/m3) compared to those areas where the air cleaners were turned-off (51.4±15.0 μg/m3). Average incabin PM2.5 concentrations were significantly lower (by 14%) in areas with air cleaners turned on (33.7±12.2 μg/m3) compared to those areas where air cleaners were turned-off (39.2± 14.4 μg/m3). In-cabin PM10 and PM2.5 concentrations ratios were similar regardless of area with air cleaners turned-on or turned-off. The in-cabin PM10 and PM2.5 concentrations were not associated with commute time. Use of air cleaners in subway trains effected reductions in in-cabin PM10 and PM2.5 concentrations.

Smoking is a disservice to not only for smokers who smoke, but also for nonsmokers due to smoke or smell. In particular, smoking harms health by increasing the discomfort associated with the smell generated by burning the cigarette, and giving rise to lung injury or cancer caused by smoke inhalation. The purpose of this study was to investigate the characteristics of various concentrations of nicotine, PM2.5, and heavy metals (As, Cr, Cd, Pb) generated by smoking according to the smoking intensity. When smokers smoked continuously, the amount of nicotine, PM2.5, Cr, and Cd produced by smoking increased proportionally and became statistically significant. However, As and Pb showed a different pattern from other materials, and the concentration increased by 2~3 times when 10 cigarettes were smoked. As for the change in PM2.5 for 12 hours immediately after smoking, about 70% of the particles were deposited on the floor or wall even in a sealed room where no ventilation was available, and the concentration naturally decreased. However, the remaining particles were found to remain in the air even though the time passed exceeded 12 hours.

About half of the South Korean population lives in the three major metropolitan areas, which are Seoul, Kyeonggi and Incheon. Among this group, more than 50% live in apartments. In this study, the relationship between the concentration of indoor VOCs and environmental factors was investigated in metropolitan apartments in the occupation stage. The maximum concentration of TVOC (total volatile organic compounds) was monitored in spring season. Among the identified VOCs, toluene was present in the highest amount, followed by terpene, aldehyde and hydrocarbon. Due to the specific indoor sources, the I/O ratio of terpene (e.g. d-limonene, α-pinene, and β-pinene) was relatively higher than that of the others. The construction year and length of residence were revealed as the environmental factors having the greatest influence on the concentration of indoor benzene, toluene, ethylbenzene, xylene, styrene and hydrocarbon, and the relationship was statistically significant. The floor and size of the apartment influenced the levels of indoor nonanal. The relationships between individual VOCs showed highly positive correlations that are statistically significant. Through the relationship study, it was found that factors including newly built apartment, short period of time after moving in, high floors and small floor area were the main factors inducing an increased concentration of indoor VOCs in apartments.

The indoor air quality of residences has been regulated by designating recommended standard levels of pollutants for newly built apartments. But as of yet, no related guideline has been established for dwellings that are already occupied. From a sociological viewpoint, the gap between the rich and poor has been gradually increasing with economic development, and this has extended to the diversification of house types and living environments. Specifically, people who have the lowest income levels may live in temporary houses such as vinyl greenhouses and shanty houses, and their living environment is mostly inadequate as a result. In this study, we surveyed the indoor air quality in normal and socially vulnerable houses after the occupation stage and tried to figure out the main factors influencing indoor air quality. Airborne fungi are detected more frequently in lower living standard houses. Put another way, the concentration of airborne bacteria and the volatile organic compound levels are much higher than in normal dwellings.

Environmental tobacco smoke (ETS) contains a large variety of substances, of which at least 50 are known to or are believed to be carcinogenic. Although the Ministry of Health and Welfare has started to prevent public exposure to ETS by enacting indoor smoking bans, some facilities still allow their customers or users to smoke indoors. In this study, indoor air quality in a pub was investigated by monitoring particulate matters (PM1.0 and PM2.5), heavy metals (As, Cd, Cr, Pb) and nicotine concentration to figure out the influence force of smoking behavior on indoor air quality. Smoking behaviors are revealed to be a major contributor the contamination of indoor air in pubs. The range of PM2.5 mass concentrations were 82.2~208.0 μg/m3 and the mean concentration of PM2.5 was 135.9 μg/m3. In the case of nicotine, the mean concentration was 12.2 μg/m3 with a range from 2.7 to 24.1 μg/m3. In the results of metal analysis, the levels of heavy metals in particulate matters in a pub were found to be much higher than those of the other public facilities.

The indoor air quality in public facilities has been well maintained as consciousness of facility owners is improved.However, the risk of PM2.5 and heavy metals in particulate matters have not been highlighted until now. So weinvestigated the particulate matters on major public transportation facilities such as subway, port and bus terminals.And we tried to figure out the characteristics of each facility groups by comparing the mass and metal concentrationbetween PM2.5 and PM10. As a results, the correlation between concentration of indoor particulate matters andthat of outdoor particulate matters shows higher strength in the case of bus terminals and port platforms thansubway platforms. However the total concentration of particulate matters and heavy metals were much higher insubway platforms than that of terminals and port platforms.

The aim of this study is to analyze the distribution of particulate matters including PM_2.5 which is known for severe adverse health effect than PM₁₀ in public facilities. The total 40 public buildings are investigated in this study and they are classified into 11 sub-groups as follows : child-care centers, medical centers, libraries, museums, bus terminals, ports, airports, railway terminals, subway stations, large-scale stores, and indoor parking lots. The mean concentration of PM₁₀ was 38.6㎍/㎥ and that of PM₁₀ in all studied facilities were lower than the Ministry of Environment's control standards. The average concentration of PM_2.5 was 27.2㎍/㎥ and that of PM_2.5 in 18 facilities were exceed the guideline of WHO (24h average value : 25㎍/㎥). The subway stations had the highest indoor level of particulate matters and the waiting area in bus terminals, railway terminals, indoor parking lots had followed in order. When comparing mean value of I/O ratio of PM₁₀, the only I/O ratio of subway stations were greater than one. In the case of PM_2.5, however, the average concentrations of PM_2.5 in indoors of subway stations, bus terminals, and indoor parking lots were higher than those of PM_2.5 in outdoors. The mean concentration of PM₁₀ and PM_2.5 were gradually increased between 6 A.M and 10 A.M and after 6 P.M in most of target buildings with increasing the number of users in thest facilities.