Many air purifiers have been developed and released with increasing PM. In generally, the performance of air purifiers has been evaluated in the environment chamber by relevant standards. However, as there is a lack of information about air cleaning performance of air purifier in the living area, consumers have difficulty with product selection. In this study, five air purifiers were tested in apartments with different structures. In order to examine the effect of air purifiers, we assumed 3 cases such as inflow of pollutants from outdoors by ventilation, smoking patterns of residents, and cooking methods (e.g., frying fish). The evaluation results showed that the efficiency of air purifier products D and B of the 3-stage configuration (pre-filter + HEPA filter + activity carbon) was the best in most experiments. In the case of the ionizer type E product, the efficiency was very low and, at times, had increased the particulate matter indoors. Considering the cost-performance ratio, it is most reasonable to use an air purifier comprising a pre-filter and a HEPA filter without an additional configuration.

The stench of various sources has become a complex issue that all governments must face and solve. n-Butanol is often used as an odor intensity reference for daily air quality monitoring and evaluation. However, its odor space, including odor sensation and odor effect, is still not fully understood, especially in wide concentration ranges. This study described n-butanol odor character profiles with objective descriptors. They are mostly presented as “odorless” or “offensive” at low concentrations, and frequently characterized as “chemical” or “medicinal” at high concentrations. The semantic differential shows that n-butanol odor is a negative emotional odor rather than a positive one. The principal component analysis shows that the representative factors of the n-butanol sensibility structure according to the sensibility evaluation are expressed with diverse sensibility vocabulary, and ‘esthetics’ represent its characterless nature. The good linearity between intensity and concentration, the near absence of gender difference, diverse odor types rather than a specific type, and ease with which to make a wide range of concentrations, makes n-butanol a candidate to be considered as a suitable standard odorant.

We developed a wet scrubber by applying cyclone flow to the gas flow and using a spiral filter structure. While the size of a new scrubber was about half that of a conventional scrubber, the device showed relatively high efficiency in pollutants removal such as particulate matter and compounds inducing odor. The new scrubber installed in a plating industry showed a higher removal efficiency of about 5% for dust, about 23% for hydrogen chloride, and about 23% for sulfur dioxide compared to the conventional scrubber. Plurality of tubes in the spiral filer housing are arranged to be vertically shifted from each other. Because the upward residual gas does not directly rise vertically, the residence time of gas between the filter plates is extended. Thus, the purification efficiency of the pollutants was enhanced in the new scrubber. In addition, the new scrubber developed in this study is more cost effective because the cost saving in manufacturing it compared with a conventional scrubber increases with increasing the size of equipment. It is expected that a scrubber with better dust collecting efficiency can be obtained by carrying out a study in connection with facilities capable of controlling acidity of washing water.

Recently, public complaints about unpleasant odor are increasing, particularly in urban areas. One of the odor sources is meat grilling restaurants in the vicinity of the residential areas. In this study, we characterized the odorous compounds generated from the stack of grilling restaurants, and evaluated the removal efficiency of the control facilities. As a result of the field investigation, the dilution index of the complex odor exceeded 500 times that of all test restaurants. The main substance was acetaldehyde. In addition, the correlation coefficient (R2) between the total odor and the sum of odor activity values (SOAV) was 0.73, a value high enough to indicate significant responsibility. The performance of the control facility has been shown to be strongly influenced by maintenance activities, such as cleaning and filter replacements.

Using computational fluid dynamics (CFD), this study simulated the air supply and exhaust conditions inside KTXSancheon train cabin to analyze the airflow, velocity, temperature, and residence time distributions. Based on the analyzed airflow in the cabin, the trajectory properties of droplets with various diameters exhaled from a passenger in a specific seat were analyzed. In the train cabin, forced airflow was formed by the operation of an air conditioning unit, while air stagnation occurred through spinning vortices at the front and rear where there were no floor outlets. Droplet particles ≤36 μm in diameter were dispersed throughout the cabin following the airflow generated by the air conditioning unit. The degree of dispersion differed according to the passenger seat location. In addition, the expelled droplets were mostly deposited on the surfaces of passenger bodies, seats, and floor. The ratio of deposited droplets to suspended droplets was increased with increasing droplet size. Further, the CFD study allowed the prediction of the possibility of exposure to exhaled droplets by estimating the dispersion and deposition properties of droplets released from a passenger in a specific seat. This study can be utilized to adjust the operation of air conditioning units and encourage the installation of air-purifying units to minimize secondary infections.

Fungus has been regulated as an air contaminant in indoor environments in Korea. To remove the contaminant, air purifiers have been used in houses. However, not much information on the status of fungal contamination in the indoor air of houses is available. The present study was carried out to investigate fungal concentration and species in the indoor air of houses using air purifiers in winter. The results of indoor air sampling of ten houses located in the cities of Incheon, Seoul, Hwaseong, and Gimpo showed that the level of fungi ranged from 9 CFU/ m3 to 782 CFU/m3. Eight out of ten houses showed a level of less than 165 CFU/m3 indicating that the fungal level is generally low. Only one house exceeded the Korean regulatory standard value of 500 CFU/m3. A total of 175 isolates were obtained and classified as three genera belonging to Aspergillus, Cladosporium, and Penicillium. Among these three genera, 15 species including four Aspergillus spp., two Cladosporium spp., and nine Penicillium spp. were identified. Regarding the detection rate of the 15 identified fungal species, A. niger was the most detected species and followed by Cladosporium cladosporioides. Three to six species were present in the individual house that was investigated. Overall, our results showed that the level of fungal concentration and species diversity are low in the indoor air of houses that use air purifiers in winter.

In this study, 102 residents in Gwangyang and Yeosu were evaluated for exposure to levels of urethral arsenic from April 2017 to June 2018. The geometric mean concentration of the urinary arsenic in the total studied was 154.30 μg/L, with the figure for the Gwangyang area being 201.18 μg/L and the figure for the Yeosu area being 200.21 μg/L, which signifies that there was no real difference between the two regions. The figures for males and females were 173.81 μg/L and 136.98 μg/L, respectively, indicating higher levels for males. In the case of males, the risk assessment of arsenic (As) showed that 0.54 does not exceed 1 and approximately 11.3% exceeded the reference value. For women, the number of hazardous materials did not exceed 1.41 and approximately 5.1% exceeded the reference value of the total arsenic exposure survey.

In this study, we listed the VOCs focusing on ozone precursors emitted from printing shops in urban areas. The emission characteristics of the VOCs from workplaces were evaluated in terms of the used inks. As a result of field measurements, more than 80% of detected VOCs showed high values of photochemical ozone creation potential (POCP). The main species were aromatic hydrocarbons such as ethylbenzene, toluene, ethyltoluene, xylene, trimethylbenzene and their isomers, and paraffin hydrocarbons such as nonane, decane, and octane. Comparative examination between pristine ink and the printing process revealed the emission of hydrocarbons with 8 to 12 carbons such as o-xylene to n-dodecane from the used inks and with 3 to 7 carbons such as acetone to 3-methylhexane from the printing process. The major contributors to ozone production in printing industries were toluene (12.2%), heptane (7.43%), and 1,2,3-trimethylbenzene (7.21%) in every step.

The aim of this study was to evaluate the odor reduction in swine farms by the application of probiotics. A total of five farms were selected from the preliminary survey based on the management scale, odor gas concentration level, and production efficiency. The application of probiotics consisted of feeding swine high concentrations of probiotics, addition of odor-reducing agents in the slurry pit, and the spraying of swine houses. The concentration of probiotics given per pig per day was above 107 cfu/g. The odor was measured before and after probiotics application for 77 days in the swine farms. With the exception of E farm, the odor concentration decreased in four farms with probiotics application. Ammonia and amine concentrations were reduced by 48.24% and 45.37% on average, respectively. The main causes of odor were hydrogen sulfide, p-cresol, and butyric acid. The total odor activity value was the lowest in D farm, followed by B, A, E, and C farms, respectively in increasing order. In the case of C farm, hydrogen sulfide accounted for 92% of the total odor activity value. In order to verify the reliability and effectiveness of probiotics at the farm site, appropriate application and monitoring should be performed continuously on the basis of the product quality evaluation system.

In this study, indoor radon concentrations were measured in 56 multiple-use facilities located in Gwangju area from December 2017 to December 2018. The average indoor radon concentration in underground space was 51.70 Bq/m3, and that of the 1st floor was 38.73 Bq/m3, indicating that the indoor radon concentration of underground space was higher than that of the 1st floor. The indoor radon concentration was investigated according to the presence or absence of underground space. The concentration of radon on the 1st floor with underground space was 37.25 Bq/m3, and the concentration of radon on the ground floor without underground space was 47.94 Bq/m3. In the absence of underground space, indoor radon concentration was high. The indoor radon concentration of buildings over 30 years old was 87.26 Bq/m3, indicating a significantly higher indoor radon concentration compared to those of buildings less than 30 years old. The indoor radon concentration was investigated according to the operation of a ventilator. The indoor radon concentration of space without an operating ventilator was 52.17 Bq/m3, and that of space with a ventilator in operation for more than 8 hours per day was 36.31 Bq/m3. This result shows that the indoor radon concentration in the space with an operating ventilator is lower than the space where the ventilator is not in operation. The indoor radon concentration in the space with an operating ventilation system was lower than that on the same floor of the same building, and the indoor radon concentration of enclosed space was about 4.4 times higher than that of open space in the same building. In addition, the indoor radon concentration was measured according to the spatial features. The concentration of indoor radon of enclosed space was 64.76 Bq/m3, which is higher than those of an open space and an active space.