Coffee is the most popular beverage in the world and various pollutants, including volatile organic compounds (VOCs), are emitted from the coffee manufacturing workplace (roasting process). In this study, we analyzed the characteristics of VOCs emissions from roasted Arabica coffee bean powder using a VOCs emission chamber with a PTR-ToF-MS. The emission test was maintained under constant temperature (20 ± 2oC) and humidity (50 ± 5%) conditions. As a result of the emission test, most of the target compounds had a high concentration in the initial period, and decreased emissions as time lapsed. Acetaldehyde showed the highest concentration and was initially 78 ppm during the test period. Acetaldehyde was followed by propionic acid at 61 ppm, propanal at 51 ppm, and isobutanal at 50 ppm. As a result of comparing the occupational exposure limits (OELs) of individual VOC emitted during the coffee roasting process, the OELs of four substances, including acetaldehyde, propionic acid, acetic acid, and pyridine were identified. Of all four substances, only pyridine exceeded the OELs, and the other compounds had levels of 10% to 30% of the OELs.

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.

Since 1974, the urban subway has been used as a major form of public transportation in Seoul, Korea. The air quality in the subway environment depends on the introduction of air pollutants from roadway air and its generation is caused by subway operation in the tunnel. In the subway tunnel, PM10 concentration was monitored from March 8 to 15, 2018 and from March 26 to 28, 2018, and compared with concentrations that are routinely monitored at the subway concourse and the nearest roadside air quality monitoring station (RAQMS). Overall PM10 concentration at the concourse was similar to that of the RAQMS. However, PM10 concentration in the tunnel was significantly higher than those of the subway concourse and RAQMS, and showed distinct diurnal variation caused by train operation. The dominant peak concentrations were highly correlated with the number of train operations per hour. The minimum PM10 concentration was observed between 2 am to 5 am when the train was not operated. This was similar to that of the RAQMS. Although the diurnal variation of the PM10 concentration at the concourse is not significant, the overall trend is similar to that in the tunnel.

The urban expressway is widely used to avoid traffic jams in highly-populated urban areas. However, vehicle exhaust can be easily transported to the neighboring area including residential buildings. In this study, we investigated the transport and penetration of vehicle exhaust into the nearby high-story residential building. Black carbon (BC) and lung deposited surface area (LDSA) concentrations were monitored every 1 min using an aethalometer (AE51, Magee) and a nanoparticle aerosol monitor (AeroTrak 9000, TSI), respectively. For comparison, the measurement was carried out in both the living room and balcony of the apartment from January 18 to January 25, 2016. The CO2 concentration indicated the presence of residents in the living room and transport of vehicle exhaust from the roadway in the balcony. Its diurnal variation showed a significant difference between weekdays and the weekend, implying the different time activity of residents and traffic volume. BC and LDSA concentrations were 1.4±1.5 μg/m3 and 53.9±45.0 μm2/cm3 indoors, and 1.9±1.0 μg/m3, 76.2±34.5 μm2/cm3 outdoors, respectively. The indoor to outdoor concentration ratios range from 0.6 to 0.8, indicating the significant influence of outdoor vehicle exhaust. The highest concentrations of BC and LDSA were observed in the morning rush hours, except for those indoors during the weekend. In particular, the outdoor effect is significant during the morning rush hours. Indoor air quality management is urgently needed for residents living near the urban expressway.

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 urban railway system is a convenient public transportation system, as it carries many people without increasing traffic congestion. However, air quality in urban railway environments is worse than ambient air quality due to the internal location of the source of air pollutants and the isolated space. In this paper, characteristics of particulate matter (PM) pollution in urban railway environments are described from the perspective of diurnal variation, chemical composition and source apportionment of PM. PM concentrations in concourse, platform, passenger cabin, and tunnel are summarized through an analysis of 34 journal articles published in Korea and overseas. This information will be helpful in developing effective policies to reduce PM pollution in urban railway environments.

While the air quality of public facilities such as daycare centers is managed by law, the management of air quality in residential buildings is not mandatory. For this reason, air quality in an apartments has not been well surveyed. In this study, we investigated the influence of cooking and ventilation on the indoor air quality in an apartment. Continuous measurements were performed using real-time monitoring instruments from June 9 to 17, 2014 in Seoul, Korea. A CO2 meter was used to measure CO2 concentration and temperature. A portable aerosol spectrometer (0.25-32 μm), a nanoparticle aerosol monitor (10-1,000 nm), and an aethalometer (total suspended particulate, black carbon) were also used. During the measurement period, ventilation and cooking activities were observed 8 and 10 times, respectively. In 5 of the observed cases, both activities were done simultaneously. During the ventilation, CO2 concentration and temperature were decreased; however, particle concentrations were increased. When cooking was done, particle concentration was increased in some cases; however, CO2 concentration and temperature were unchanged. Combined cased CO2 concentration and temperature were decreased and particle concentrations were increased.

The number of children who use day-care centers is increasing. Most indoor air quality (IAQ) management has been based on daily average pollutant concentrations measured once a year. A more comprehensive management of IAQ is needed to protect children’s health from air pollutants in day-care centers. In this study, we investigated the weekly variation of air pollutant concentrations in a nursing room of a day-care center located at the roadside for a week in June of 2014. Average concentrations of CO2, PM10, black carbon, and total surface area of lungdeposited particles during nursing time of the day-care center were 510 ppm, 27.8 μg/m3, 1.87 μg/m3, and 30.6 μm2/cm3, respectively, with a similar diurnal pattern shown on weekdays.

Since people spend more than 85% of their time indoors, understanding indoor aerosol behavior is important in order to protect human health against aerosol exposure. In this article, exposure, behavior, and control technologies for indoor aerosols are addressed. Previous studies conducted in Korea during the period from 2004 to 2016 were reviewed. Most studies were focused on field surveys of PM10 concentration in public facilities regulated by law. More fundamental studies are needed in order to control indoor aerosols effectively due to the fact that Korea has different building structures and lifestyles compared with western countries.

A single-stage electrostatic precipitator (ESP) was evaluated in terms of its performance in removing dust in subway tunnels. A wire-to-plate type ESP was tested in a small-scale wind tunnel. The effects of wire-to-wire spacing (2040 mm) and the material connecting wire-to-wire on the performance of ESP were investigated, with varying applied voltage and airflow velocity. A narrower wire-to-wire spacing showed higher collection efficiency at the same applied voltage. Lower electrical resistivity of material connecting wire to wire was more effective. Ozone generation in subway tunnel applications was insignificant.

It is well known that smoking generates harmful air pollutants. With smoking in buildings as well as in the streets prohibited, the need for smoking rooms has emerged. In this study, particle and CO contamination in a 63.6 m3 smoking room was experimentally investigated using Korean tobacco. Tobacco smoking was artificially simulated using a smoking machine. The number and size distribution of particles ranging from 10-420 nm and 0.25-32 μm were measured using a Nanoscan (TSI model 3910) and a portable aerosol spectrometer (Grimm model 1.109), respectively. CO concentration was also monitored using an IAQ monitor (Graywolf IAQ-Xtra 610). Four tobaccos were simultaneously smoked in each experiment, and the experiment was repeated four times. Maximum CO concentrations of 7-10 ppm were observed and high concentrations of particles (176,000-1,115,000 particles/cm3 for 10-420 nm, 3,700-5,200 particles/cm3 for 0.25-32 μm) were also monitored. The dominant size of tobacco particles was about 100 nm in diameter.

Day-care center is one of living micro-environments for children. In urban area, day-care centers may be influencedby air pollutants emitted from the vehicle exhaust. In this work, diurnal variation of major pollutants and effectof outdoor air on indoor air quality were investigated using real-time instruments for a day-care center locatednear the heavy road. 48-h continuous monitoring at both indoor and outdoor were made in summer. The day-care center equipped with ceiling system air-conditioners was operated from 7:30 a.m. to 19:30 p.m. Indoor CO₂concentration responded greatly to the human activity. Indoor NO₂ concentration shows a big difference betweendaytime and nighttime, implying that outdoor NO₂ may penetrate into the indoor through opening of doors orwindows during the daytime. Indoor to outdoor concentration ratio of submicron particle surface area is <1 dueto the penetration of outdoor ultrafine particles.

Bacillus thuringiensis (B. t.) strains are important microorganism because they produced a large amount of δ-endotoxin protein per bacterial cell and their toxins are highly toxic to Lepidoptera, Coleoptera, and Diptera depending on B. t. To date, more than a hundred Cry proteins have been identified and classified into 195 holotypes, based on the amino acid sequence identity. The Cry proteins or cry genes from the Korean native B. t. isolates in this study were not identified yet. The electrospray ionization of quadrupole time of flight mass spectrometry (ESI Q-TOF MS) was used to get the internal amino acid sequences of the endotoxin-spore culture mixtures of B. t. isolates, for which polymerase chain reaction (PCR) techniques were unable to detect the cognate genes. Most of Cry proteins seperated, excized, and extracted from the one dimensional - polyacrylamide gel electrophoresis (1D-PAGE), instead of 2D-PAGE, were matched with protein databases using MS-MASCOT search program. The internal amino acid sequences which were submitted to protein BLAST (basic local alignment search tool) had partially homology with the Cry protein databases. Hence, present data strongly suggest that the de novo amino acid sequencing and ESI Q-TOF/MS analysis along with MASCOT search could be used as a simple and rapid method for detection of novel Cry toxins from B. t. isolates and identification of B. t. isolates.

누룩에서 분리한 Rhizopus japonicus T2, Aspergillus oryzae L2 및 Hansenula sp. BC26을 밀기울에 접종 및 배양하여 제조한 개량누룩으로 양조한 탁주술덧과, 기존의 발효제인 시판누룩 및 쌀입국으로 양조한 탁주술덧의 중요 향미성분을 분석 비교하였다. 향기성분인 isoamyl alcohol, isobutyl alcohol 및 ethyl acetate의 함량은 개량누룩 술덧이 시판누룩 술덧이나 쌀입국 술덧보다 훨씬 높았다. 주된 유기산은 개량누룩 술덧은 젖산, 푸말산 및 호박산이었고, 시판누룩 술덧은 젖산 및 초산이었으며, 쌀입국 술덧은 구연산, 젖산 및 호박산이었다. 유기산의 총량은 시판누룩 술덧 5, 146 ㎎/L, 쌀입국 술덧 1, 706 ㎎/L, 개량누룩 술덧 1, 388 ㎎/L이었다. 주된 유리아미노산은 개량누룩 술덧은 glutamic acid, alanine, proline 및 histidine이었고, 시판누룩 술덧은 glutamic acid, proline, leucine 및 histidin이었으며, 쌀입국 술덧은 arginine, proline 및 glutamic acid이었다. 유리아미노산의 총량은 개량누룩 술덧 14, 090 ㎎/L, 시판누룩 술덧 12, 202 ㎎/L, 쌀입국 술덧 7, 152 ㎎/L이었다. 이상의 결과들로 볼 때 개량누룩 술덧이 기존 발효제의 술덧보다 좋은 것으로 생각되었다.

자색고구마 분말을 0∼5%를 첨가하여 호상 요구르트를 제조하여 요구르트의 품질 및 기호성에 미치는 영향을 검토한 결과는 다음과 같다. 자색고구마첨가에 의해 산도, 당도, 유산균수가 대조구에 비해 높게 나타났으며 요구르트의 색택은 자색고구마 첨가량이 많을수록 lightness와 yellowness는 감소되고 redness는 증가하면서 점도는 크게 상승하였다. 요구르트의 관능성을 보면 조직감과 색은 대조구보다 첨가구에서 양호했으며 맛에서는 차이가 없었고 전체적인 기호도는 자색고구마 3∼4% 첨가구에서 가장 우수하였다.

With the development of nanotechnology, nanomaterials are used in various fields. Therefore, the interest regarding the safety of nanomaterial use is increasing and much effort is diverted toward establishment of exposure assessment and management methods. Occupational exposure limits (OELs) are effectively used to protect the health of workers in various industrial workplaces. This study aimed to propose an OEL for domestic multi-walled carbon nanotubes (MWCNTs) based on animal inhalation toxicity test. Basic procedure for development of OELs was examined. For OEL estimation, epidemiological study and quantitative risk assessment are generally performed based on toxicity data. In addition, inhalation toxicity data-based no observed adverse effect level (NOAEL) and benchmark dose (BMD) are estimated to obtain the OEL. Three different estimation processes (NEDO in Japan, NIOSH in USA, and Baytubes in Germany) of OELs for carbon nanotubes (CNTs) were intensively reviewed. From the rat inhalation toxicity test for MWCNTs manufactured in Korea, a NOAEL of 0.98 mg/㎥ was derived. Using the simple equation for estimation of OEL suggested by NEDO, the OEL of 142 μg/㎥ was estimated for the MWCNT manufacturing workplace. Here, we used test rat and Korean human data and adopted 36 as an uncertainty factor. The OEL for MWCNT estimated in this work is higher than those (2-80 μg/㎥) suggested by previous investigators. It may be greatly caused by different physicochemical properties of MWCNT and their dispersion method and test rat data. For setting of regulatory OELs in CNT workplaces, further epidemiological studies in addition to animal studies are needed. More advanced technical methods such as CNT dispersion in air and liquid should be also developed.