Odorous compounds from the operation of wastewater treatment plants (WWTPs) have increasingly become public health concerns and civil complaints. This study identifies priority management stages in WWTPs by quantitatively analyzing the distribution of complex odor and designated odor substances across key processes using a dimensionless tool (the Odor Activity Value, OAV), while providing a statistical basis and operational strategies for efficient odor mitigation in public facilities. Although there was a very poor correlation between designated odorous concentrations and complex odor level (dilution ratio), the application of the OAV yielded much more accurate results with a strong correlation (R2 = 0.7) specifically at high-temperature condition. Odor potential in the wastewater treatment processes fluctuates substantially depending on the specific unit. Statistical analysis using Kruskal–Wallis tests demonstrated that influent and sludge treatment process (return flow and centrate) produce much higher odor intensities compared to the biological reactor and secondary clarifier. Based on PERMANOVA analysis, differences in the profiles of complex odor and the OAVs of designated odorants across 6 treatment stages explained 64.1% of the total variance. Principal Coordinates Analysis (PCoA) showed that sludge treatment processes form a distinct, unique cluster, whereas sewage treatment streams present a more gradual transition of odor profiles. Statistical assessment using the Mann-Whitney U test demonstrated that mean odorants levels did not have considerable shift under high-temperature and low-temperature conditions. However, the sensory perception in higher temperatures enhanced relative to the OAVs. In conclusion, the OAV is an effective dimensionless tool, as it establishes priorities in odor management and control, offering a practical supplementary indicator for addressing civil complaints. These findings provide a robust foundation for optimizing deodorization systems designs and operational efficiency of odor mitigation systems within WWTPs.

This study investigated indoor air quality (IAQ) in 302 facilities (consisting of 638 monitoring points) across five types of multi-use facilities for the health of vulnerable populations in Seoul. The facility types consisted of the following: ICPs (indoor children’s playgrounds), PCCs (postnatal care centers), ECFs (elderly care facilities), HCFs (health care facilities), and CCCs (child care centers). The investigation was carried out over a 1-year period, from January to December 2024. The objective of this research was to provide a scientific basis for IAQ management by identifying characteristics specific to facility types and potential risk levels for vulnerable populations in Seoul. Five indoor air pollutants (PM10, PM2.5, CO2, HCHO, and TAB) were continuously measured, and their concentration distributions, temporal variability, and multi-pollutant patterns were analyzed using data visualization and statistical methods. Boxplots and ridgeline plots characterized distributions and seasonality by facility type, while star plots and K-means clustering were used to examine multi-pollutant combinations and inter-facility pattern differences. Most measurements were within national IAQ standards. However, HCFs and PCCs exhibited relatively higher mean levels and variability of HCHO and TAB, indicating a greater need to control chemical and microbiological sources. CO2 concentrations approached or temporarily exceeded the national standard, particularly in HCFs, reflecting differences in occupant density, occupancy time, and ventilation management. Kruskal-Wallis and pairwise Wilcoxon rank-sum tests revealed statistically significant differences among facility types, particularly for CO2 and HCHO, consistent with the visualized multi-pollutant profiles. K-means clustering identified three IAQ patterns-multi-pollutant-elevated, activity/ventilation-influenced, and low-pollutionindicating that management needs may vary across facilities despite uniform national standards. These findings provide a methodological basis for IAQ big data analysis, policy making, and supporting future research integrating multi-year, outdoor, building, activity, and health data.

Airborne microplastics (AMPs), known to be persistent pollutants, have recently been detected in the atmosphere and even in human lung tissue, raising concerns about potential human respiratory exposure. In light of these concerns, this study aimed to investigate the distribution and composition of AMPs in Seoul. μ-Raman spectroscopy was employed to identify fine particles (≥5 μm) and to contribute to the development of standardized monitoring protocols. Monthly air sampling was conducted from September 2023 to March 2024 at an urban rooftop site using a PM10 air sampler. Samples were pretreated with hydrogen peroxide to remove organic matter, then filtered through a silicon filter. μ-Raman spectroscopy was applied for qualitative and quantitative analysis of microplastics. The mean concentration of AMPs was 74.0 ± 29.9 particles/m3, with polyethylene (46.7%) and polystyrene (21.8%) being the most prevalent polymer types. Most particles (64.5%) were in the size range of 5–10 μm, and fragment type particles accounted for 98.9% of the total. These results indicate that respirable microplastics are commonly present in urban air and that polymer composition may reflect both material properties and usage patterns. This research provides baseline data for future exposure and risk assessments and supports the need for international standardization of airborne microplastic analysis protocols.

Time-series and spatial analysis of collected odor complaints in Seoul megacity during 2014~2021 were conducted for the characterization of odor complaints emitted from the living environment. The ratio of odor complaints in the environmental complaints was 16.7%, and odor complaints increased 3.3 times from 9,053 cases in 2014 to a maximum of 29,425 cases in 2019. In the time-based evaluation (monthly, daily (day of the week), and hourly variations), the highest number of complaints occurred in June, Monday, and 9:00 AM, respectively. While the lowest number of complaints occurred in December, Sunday, and 3:00 AM, respectively. Among 25 provinces in Seoul megacity, the odor complaints that occurred from 2014 to 2021 were concentrated in Eunpyeonggu. The odor complaints of Seodaemun-gu and Nowon-gu occurred at the highest levels in January-February and June, respectively. Based on the characteristics of odor complaint occurrence according to the above time-series and spatial analyses, more effective odor management and control can be implemented by focusing on those hotspot areas and specific time periods.

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.

Following the social requirement to strengthen field supervision of the asbestos containing materials (ACM) abatement process with regard to asbestos school buildings, this study was conducted to understand the status and characteristics of airborne asbestos that may potentially occur after the ACM abatement process is completed. In the area where a series of asbestos abatement processes were finally completed, comprehensive area air sampling was performed. For sample analysis, Transmission Electron Microscopy (TEM) was used according to The Asbestos Hazard Emergency Response Act (AHERA) method and Phase Contrast Microscopy (PCM) analysis was also performed. Airborne asbestos was detected in 29.5% of the total samples, and the average concentration was 0.0039 ± 0.0123 s/cc (12.3 ± 38.9 s/mm2). 4.5% of the total samples exceeded the AHERA standard (70.0 s/mm2) and the average concentration was 0.0528 ± 0.0256 s/cc (167.2 ± 82.0 s/mm2). Airborne asbestos was no longer detected at the point when AHERA is exceeded after re-cleaning. Most of the detected asbestos was chrysotile (94.4%) and the structure types of asbestos were Matrix (41.4%), Fiber (39.9%), Bundle (10.8%), and Cluster (7.8%). Among the asbestos structures detected through transmission electron microscope analysis, the asbestos structures satisfying PCM-equivalent structures were found to be 6% of the detected asbestos, indicating that there is a limitation of the PCM analysis to check the airborne asbestos in that area. As a result of reviewing the status of airborne asbestos that may potentially occur and the type and dimensions of asbestos structure detected in the area, since the airborne asbestos exposure caused by poor field supervision for the ACM abatement process could not be ruled out, thorough management is necessary. In addition, the result of this study could be used as scientific evidence for establishing and strengthening policies related to ACM abatement, including cases of school buildings.

This study investigated 180 students’ indoor environmental awareness of rest spaces and measured the indoor and outdoor concentrations of PM10, TVOCs, and HCHO in 8 rest spaces from October 2019. 89.4% of the students responded that they use rest spaces at least once a day and most of the respondents are using rest spaces in the university. The largest number of students responded to the tight space as the main cause of air pollution in rest spaces. 62.1% of the students answered they experienced health symptoms from using rest spaces. Among them, 32.5% said they experienced irritation symptoms of eyes, neck, nose, and 12.1% answered that they experienced headaches. Indoor PM10, TVOCs, and HCHO levels did not exceed indoor air quality recommendations nor the maintenance standard for multi-use facilities. Indoor PM10, TVOCs, and HCHO levels did not exceed indoor air quality recommendations nor the maintenance standard for multi-use facilities. According to the type of rest space, concentrations of PM10, TVOCs, and HCHO were higher among the closed-type than open-type rest space. Even if the concentration of pollutants is less than the environmental standard, continuous exposure may cause negative health effects. In addition, considering that 62.1% of the respondents experienced health symptoms, it is deemed necessary to take measures to manage indoor environments in rest spaces and to develop measures to reduce pollutants.

This study conducted a survey on environmental awareness and analyzed outdoor PM10 and heavy metals (cadmium, lead) for 60 local residents living in the Gwangyang national industrial complex from July 2019. 40.0% of subjects responded that local environmental pollution was serious. Especially, there was a high proportion of residents living near the industrial complex or roads where it was perceived that local environmental pollution was serious. The average concentration of PM10 in the outdoors of the houses was 10.95 μg/m3 and the average concentration of heavy metals in PM10 was 1.90 ng/m3 for Cd and 24.92 ng/m3 for Pb. Overall, the average concentration of PM10 and heavy metals revealed a tendency to be high in the houses located near the industrial complex or the roads. As a result of a risk assessment carried out, the cancer risk of Cd was estimated to exceed 106 in the CTE, RME and Monte Carlo analysis. These results suggest that the urgent implementation of specific environmental health education for local residents is necessary.

This study was performed to investigate the characteristics of VOCs and carbonyl compounds emitted by smallscale master, offset, and screen printing facilities. During the printing process, concentration measurements of indoor samples were made at each on the printer equipment and the indoor center of the facility. In each case, the window or door served as natural ventilation, and concentration measurements of outdoor samples were made at each air exit point. The results showed that in all printing facilities, the levels of VOCs and carbonyl compounds were much higher in printer equipment compared to indoor levels. Comparative examination of VOCs between printer equipment and the indoors of the facility, the main species of master and offset printer equipment were Methyl isocyanide, 2,2,6-Trimethyloctane, 2,2-Dimethyldecane, 3,7-Dimethyldecane, Toluene, Acetonitrile, and 3- Methoxy-3-methylbutanol. The main species of the indoors of master and offset facilities were Toluene, 2,2,6- Trimethyl-octane, Isopropyl alcohol, 3-Methoxy–3- methylbutanol, Nonane, and Acetone. However, in the screen printing facility, the printer and indoor emission compounds were the same such as 2-Methyl-cyclopentanone, Cyclohexanone, Ethylbenzene, and p-Xylene. Among the compounds released to the outside, Toluene and Acetone were the most abundant species of VOCs and carbonyl compounds, respectively.

This study examined the relevance of impact factors using survey data, standardized mortality rates, and medical utilization rates of study subjects in the Namhae and Hadong regions. The study subjects were found to have lived in the area for more than 20 years, and in terms of lifestyle, they did not smoke, but the rate of drinking was high and showed little exercise. As a result of analysis through logistic regression analysis, it was found that angina pectoris, myocardial infarction and anemia were affected by exercise status, and allergic rhinitis disease showed significant results depending on the presence of smoking. The standardized mortality rate of men in chronic lower respiratory tract diseases in the Namhae and Hadong regions was higher than in the nation. In the case of allergic rhinitis, both men and women in Namhae were slightly lower than those in Nation, and in Hadong, both men and women were higher than in Nation.

The use of printing inks containing organic solvents by the master, offset and screen printing process implies the release of volatile organic compounds (VOCs) to the work environment. In this study, the volatile content of inks was evaluated by using a thermogravimetric analyzer (TGA), in which the solvent is evaporated. And, to identify the the characterization of VOCs emissions from printing inks, air samples were collected in a thermal extractor (TE) and analyzed by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Weight loss curves suggest that there are two main stages, such as dry fastening and chemical curing. As the result, the first stage of mass loss (below 100oC) was due to VOC evaporation. At this stage, master and offset inks are slightly stable thermally up to 100oC, but screen inks weight loss increases distinctly beyond 25oC. The volatile content is higher in screen inks than in the master and offset inks. The results of the mass-specific TVOC emission rate of the master, offset, and screen inks were 6.3 μg/(g·h), 8.4 μg/(g·h), and 212.2 μg/(g·h), respectively. Then the TVOC emission rate of the screen inks was 25~33 times higher than that of the master and offset inks. The main species were 1-Ethyl-2-pyrrolidinone, 1,2,4-Trimethylbenzene, 1,2,3-Trimethylbenzene, 1,2,4,5-Tetramethylbenzene, 1-Methoxy-2- propanol, Decane, Undecane, and Nonane.

This study was performed to assess particulate matter removal efficiency of domestic air cleaner products in a field condition. The assessment also included air cleaners with different air removal mechanisms. The particulate matter (PM2.5) removal test with a different air removal mechanism using air cleaners showed that the electrostatic precipitation technique showed better performance compared with HEPA filters and other types of systems. Its removal efficiency was almost 95% in one of our operation times in the given test condition. It was assumed that not only the type of removal system but also the individual design, supply and exhaust system, and the automatically controlled air volume are involved in the removal efficiency. With respect to the area of application, tests with air cleaners for 40 m2, 60 m2, and 80 m2 areas revealed that particulate matter removal efficiency increased with the air cleaner that had a broad area of application. However, particulate matter removal efficiency by air cleaners did not correspondingly increase with the increase of the area of application. Moreover, the installation location did not influence particulate matter removal efficiency. Our results are expected to be used as the basic information for indoor air quality improvement and prediction using air cleaners.

The purpose of this study was to characterize the concentration of and evaluate the pollution level of indoor air pollutants among the public-use facilities located in Seoul that are mainly used by medically sensitive users. The data used in this study were analyzed based on the supervision data provided by Seoul Metropolitan Government Research Institute of Public Health and the Environment. There were 399 nursery schools, 188 medical facilities, 42 elderly care facilities and 96 postnatal care centers. The indoor air pollutants to be investigated were analyzed for PM10, CO2, HCHO, TAB and CO. Through the analysis, it was found that among the surveyed pollutants, TAB levels exceeded the criteria most often, in 54 facilities. Among the surveyed facilities, nursery schools exceeded the criteria most often, in 49 facilities. There was a statistically significant difference between the pollutants in each facility (p<05). However, considering the characteristics of the data used in this study, additional factors should be investigated for factors affecting the concentration of each indoor air pollutant for a more rational evaluation.