The adsorption method that is widely used in the field of odor control generally utilizes activated carbon. However, the development of an economical and efficient adsorbent is required due to the increased use of activated carbon and the high cost of raw materials. Accordingly, the use of waste as a raw material for new adsorbents is attracting attention both in Korea and abroad. In this study, the current status of domestic and overseas waste generation, characteristics of adsorbents, and research trends were investigated, and through this, it was found that a waste-derived adsorbent was an adequate substitute in terms of adsorption capacity and price compared to activated carbon.

This study investigated the odor dilution rate at 15 locations around three schools in Seoul using an onsite olfactometer. In addition, odor intensity, odor quality, and hedonic tone by direct sensory method were measured along with measurement of the field odor dilution rate, and instrument analysis using odor sensor array and TD-GC was also measured. Onsite olfactometer measurements show that only one of the three schools measured odors exceeding the strict emission acceptance standard of 10 at three points. The average odor intensity at each point measured by the direct sensory method of five persons was in the range of 2.7 to 0.3. The difference in the number of odor dilution rates around schools in Seoul could be related to the level of income by region. The odor environment around each school was judged to be well managed in areas with higher income levels, indicating a lower odor dilution rate. The correlation coeffcient between the odor intensity measured by the direct sensory method and the onsite olfactometer was 0.79, indicating high correlation. The correlation coefficient of sensor array and TD-GC toward the odor intensity was -0.28 and 0.02, respectively. This suggests that a method based on a person's sense of smell should be introduced when measuring low-level odor dilution rates in non-industrial areas, such as school zones.

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.

The sampling bag is used as a storage container for odor gas samples. It is known that the substances recovery rate of odor bags decreases during storage time, and the degree of recovery varies depending on the characteristics of the gas sample and the material of the bag. This study investigated the recovery rate of VFA (ACA, PPA, BTA, VLA) in PEA bags during storage time. In addition, a model was developed to estimate the recovery rate of each substance as a function of time. Standard gas (ACA, PPA, BTA, VLA mixed) recovery rate was used for the model development. The concentration of the compound in the bag was measured by SIFT-MS at intervals of 1 to 2 hours. The recovery rate according to the storage time was calculated as the ratio to the initial concentration. The recovery rate of each substance according to the storage period (12h, 24h, 36h, 48h) was ACA (66.2%, 62.8%, 55.6%, 52.0%), PPA (77.6%, 72.1%, 63.0%, 58.1%, 86.6%), BTA (86.6%, 81.3%, 71.6%, 66.9%), VLA (94.8%, 89.0%, 76.6%, 71.7%). The recovery rate continued to decrease over the course of 48 hours of storage time. ACA, PPA, and BTA showed the greatest decrease within the initial 12 hours, which is form of exponential decrease. Therefore, we considered a 1~3 degree polynomial regression model and a 1~2 degree exponential decay model. Each developed model was evaluated by r², RMSE, MAPE, AIC, and then a model for each substance was selected. Selected models were tested with recovery rate data from swine farm odor samples. Only the ACA model exhibited a good performance (r² = 0.76).

Two lab-scale trickle-bed type biofilters with a single fungal species (Aspergillus fumigatus, Acidomyces acidophilus, respectively) have been studied to investigate the simultaneous removal of inorganic (hydrogen sulfide) and organic (butyl acetate) compounds. The biofilter with Aspergillus fumigatus treated simultaneously two different compounds with removal capacity of 1,511 mgS/m3/hr and 6,324 mgC/m3/hr; and the biofilter inoculated with Acidomyces acidophilus had the removal capacity of 1,254 mgS/m3/hr and 6,045 mgC/m3/hr. Stable operational performance was observed in both biofilters under an acidic condition of pH 2 to 4. Based on pseudo-first-order removal rates as a function of depth in the biofilter, Aspergillus fumigatus showed a twice faster rate of hydrogen sulfide removal than Acidomyces acidophilus, 15.9% (Aspergillus fumigatus) and 17.9% (Acidomyces acidophilus) of total sulfur removed were oxidized to produce sulfates, and 77.8% (Aspergillus fumigatus) and 79.4% (Acidomyces acidophilus) were accumulated in the form of S0 through the bed in both biofilters, respectively.

The degree and intensity of unpleasant and disgusting odors perceived through a person's sense of smell can vary depending on personal or social and cultural characteristics. In addition, it is not effective to manage odors solely on the basis of concentration levels because odors can be combined according to temperature, humidity, and frequency, so that they can be recognized differently even if the same person smells the same substance. The mobile odor application was developed to enable real time monitoring of odor characteristics reflecting the actual condition of the field. Accordingly, the Green Future Foundation, a civic group, conducted an environmental campaign to record and share the information of odors in school zone using the first version of the application. The real time monitoring of field odor was able to improve the problems of the current standard methods for the examination and assessment of odors. However, with regard to the first version of the application, the process and results of odor recording through odor measurement applied the direct olfactory method and were less relevant. Therefore, it was difficult to organize data due to duplicate selection. For that reason, this study was conducted to overcome the problems of the first version of the mobile application and to effectively and accurately reflect odors and personal characteristics. This odor application that has been developed is able to monitor and assess odors based on 5 features: classification, character, strength level, hedonic tone, and acceptability.

This study was undertaken to investigate whether HEPA filter-equipped air purifiers can remove aerosolized virus, whether the removed virus can re-scatter through the filter, and how long the removed virus keeps its infectivity in the filter. For this investigation, six HEPA filter-equipped air purifiers produced by different companies were tested against PhiX174 and MS2 phages aerosolized by nebulizers. For viral detection from the air, LB agar plates covered with Escherichia coli hosts and an Andersen air sampler were used, and from the surface, the swab method was used. Both the aerosolized PhiX174 and MS2 viruses absorbed by the HEPA filters in the air purifiers were not detected from the air through filters or the surface of the outlet of the air purifiers. During the operation of the air purifiers at medium mode, the infectious viral concentration of these viruses in the HEPA filters decreased to 0%~12.3% as the time period passed. These results regarding infectious viral concentration differences were assumed to be due to the different wind speed and air volume among the six air purifiers. Based on observations over 5 days, the infectious viral concentration of the PhiX174 phage was 8,600 times lower when the air purifier was operated than when it was not operated. Overall, our results demonstrate that HEPA filter-equipped air purifiers can efficiently remove the two aerosolized viruses and the removed viruses in the HEPA filter could not re-spread and maintain their infectivity.

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.