• 한국환경보건학회지
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• 제50권1호
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• pp.6-15
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• 2024

Background: People's activities have been restricted due to the COVID-19 pandemic. These changes in activity patterns may lead to a decrease in fine particulate matter (PM_2.5) concentrations. Additionally, the level of population exposure to PM_2.5 may be changed. Objectives: This study aimed to analyze the impact of population movement and meteorological factors on the distribution of PM_2.5 concentrations before and after the outbreak of COVID-19. Methods: The study area was Guro-gu in Seoul. The research period was selected as January to March 2020, a period of significant population movement changes caused by COVID-19. The evaluation of the dynamic population was conducted by calculating the absolute difference in population numbers between consecutive hours and comparing them to determine the daily average. Ambient PM_2.5 concentrations were estimated for each grid using ordinary kriging in Python. For the population exposure assessment, the population-weighted average concentration was calculated by determining the indoor to outdoor population for each grid and applying the indoor to outdoor ratio to the ambient PM_2.5 concentration. To assess the factors influencing changes in the ambient PM_2.5 concentration, a statistical analysis was conducted, incorporating population mobility and meteorological factors. Results: Through statistical analysis, the correlation between ambient PM_2.5 concentration and population movement was positive on both weekends and weekdays (r=0.71, r=0.266). The results confirmed that most of the relationships were positive, suggesting that a decrease in human activity can lead to a decrease in PM_2.5 concentrations. In addition, when population-weighted concentration averages were calculated and the exposure level of the population group was compared before and after the COVID-19 outbreak, the proportion of people exceeding the air quality standard decreased by approximately 15.5%. Conclusions: Human activities can impact ambient concentrations of PM_2.5, potentially altering the levels of PM_2.5 exposure in the population.

• Asian Journal of Atmospheric Environment
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• 제2권1호
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• pp.54-59
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• 2008

The most pivotal approach to improve subway indoor air quality (IAQ) is to examine the emission sources and particulate behavior. Therefore, the main objective of this study is to investigate the particulate behavior in the subway. In order to examine IAQ in the subway, a sampling and measurement campaign was carried out for 35 sites during the summer and winter seasons from May, 2005 to February, 2006. In case of 24 hour measurement, the mean concentrations ($PM_{10}$-24 hr) of platform and waiting room were $156.18{\pm}53.79{\mu}g/m^3$ and $111.00{\pm}53.31{\mu}g/ m^3$. Besides, as a result of 20 hour measurement, the mean concentrations ($PM_{10}$-20 hr) of platform and waiting room were $146.09{\pm}53.71{\mu}g/m^3$ and $99.08{\pm}42.77{\mu}g/m^3$, respectively. In general, $PM_{10}$-24 hr was higher than $PM_{10}$-20 hr, and both PM concentrations showed a high correlation coefficient (r=0.803). It was found that the $PM_{2.5}$ concentration ($l09.56{\pm}28.24{\mu}g/m^3$) in winter was higher than that ($83.66{\pm}57.82{\mu}g/m^3$) in summer.

• 한국산업보건학회지
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• 제10권1호
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• pp.160-169
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• 2000

Daily indoor and outdoor nitrogen dioxide ($NO_2$) concentration for 30 days were measured in 28 houses with questionnaire of housing characteristics in Brisbane, Australia. Using mass balance equation and regression analysis, penetration factors and source strength factors were calculated. The penetration factors of 27 houses except one house were between zero and 1, though penetration factor should be between zero and 1 by means of mass balance equation. Relationship between indoor and outdoor concentrations in each 27 house was calculated using regression analysis. According to the obtained linear regression equation, the slope means penetration factor and the intercept means source strength factor. Calculated mean and standard deviation of coefficients of determination ($R^2$) in electric and gas range houses were $0.70{\pm}0.13$ and $0.57{\pm}0.21$, respectively. The source strength factors were more than zero in 27 houses. Mean and standard deviation of slopes in electric and gas range houses were $0.65{\pm}0.18$ and $0.56{\pm}0.12$, respectively. Mean and standard deviation of intercepts in electric and gas range houses were $1.49{\pm}1.25$ and $5.77{\pm}3.55$, respectively. Air exchange rate and source strength were calculated from penetration factor and source strength factor, respectively. Geometric mean and standard deviation of calculated air exchange rates in 27 houses were $1.1/hr{\pm}1.5$. Presence of gas range was the most significant factor contributing to indoor $NO_2$ level in house characteristics (p=0.003). In gas range houses, source strengths ranged from 4.1 to $33.1cm^3/hr{\cdot}m^3$ with a mean $12.7cm^3/hr{\cdot}m^3$ and a standard deviation 9.8. The source strengths of gas range houses were significantly different from those of electric range houses by t-test (p<0.001)

• 한국농촌건축학회논문집
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• 제22권2호
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• pp.9-17
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• 2020

The ratio of the deterioration housing in rural area was 29.6%, but it was 18.3% in urban area based on a 2018 survey. In consideration of the point, this study aims to analyze the actual condition of indoor air quality in rural houses to provide basic data for improving the indoor air environment. It was investigated 15housings of Hongseong-gun, Chungchengnam-do. To investigate the correlation between indoor air quality and housing type, both the field survey of housing type and precision diagnosis of concentration of indoor air pollutants such as HCHO, TVOC, Fine dust(PM-10, PM-2.5), CO₂, Radon. The results of this study are as follows. First, according to the average value of each element of rural old housing, the construction year was distributed in 1939~2004, and 12households(80%) living in houses older than 30years have passed for about 46years. As for the housing area, more than 12houses(80%) of 60㎡ or more and 3 houses (20%) of less than 60㎡ were often living in relatively small-scale housing. Second, as a result of measuring indoor air pollutants in rural houses, substances exceeding the standard values were found in HCHO, TVOC, CO₂. Third, in the case of Fine dust and Radon, none of such factors were exceeded the standard. Fourth, there was no significant difference in indoor air quality depending on housing type in rural houses. This paper is expected to contribute to the regional development projects and effective implementation of rural policies.

• 한국환경보건학회지
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• 제50권1호
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• pp.36-42
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• 2024

Background: The use of scented candles and incense sticks, both of which are household products that are burned for indoor deodorization and calming effects, is increasing. Fine dust has been designated as a group 1 carcinogen by the International Agency for Research on Cancer. Volatile organic compounds (VOCs) affect air pollution and can cause diseases. Objectives: This study aims to determine the effect on indoor air quality by measuring PM_2.5 and VOCs generated when burning scented candles and incense sticks. Methods: Scented candles and incense sticks were selected as household products to burn. As for the target sample, top-selling products (five types of scented candles, five types of incense sticks) were purchased online. The PM_2.5 concentration according to time was measured immediately next to the sample and three meters away from each other in an enclosed space using a real-time aerosol photometer. VOCs were collected as samples under the same conditions using Tenax tubes and were quantitatively analyzed by TD-GC/MS. Results: In the case of scented candles, the concentration of PM_2.5 did not increase during combustion and after being extinguished by placing a cover on the candle. For the incense sticks, the concentration of PM_2.5 averaged 1,901.27 ㎍/m³. After burning scented candles and incense sticks, some VOCs concentrations were increased such as ethyl acetate and BTEX (benzene, toluene, ethylbenzene, xylene). Conclusions: Therefore, when using scented candles, extinguishment by placing a cover on the candle can be expected to reduce PM_2.5. It is advisable to avoid using incense sticks because PM_2.5 concentration increases from the start of combustion.

• 한국환경복원기술학회지
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• 제23권5호
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• pp.73-86
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• 2020

In the modern era, the elementary schools in the Republic of Korea are advanced with the competitive world. Thus advancement in technology, and other factors in the elementary schools are releases some kind of particulate matter (PM), which causes deleterious effects on school students health, academic program, growth and development. The school students are susceptible to PM particularly, PM₁₀ and PM_2.5. Based on this hazardous effect of PM on school students we conducted the research on the elementary schools class rooms by introducing vertical gardening system to get the schools "ever green". The main aim of this study is to investigate the environmental factors in the educational effect program in the class rooms and indoor air quality changes. For the educational effect, the 4th operation program was applied to 2 schools for 2 hours once a month from September to December 2019. Each school conducted a survey on satisfaction, plant friendliness, and environmental sensibilities, targeting classes that participated in the green school program and those who did not. The environmental effects were monitored by installing indoor air quality facility in the program participating classes and the non-participating classes. From November 2019 to December 2019, three factors were measured: PM10, PM2.5, and humidity. The results were analyzed by T-test using the SPSS 24.0 software program. As a result of the analysis, student's overall satisfaction with the program and their intention to re-engage were high in terms of educational effect. It was also found to be effective in emotional, educational, social, and physical aspects. In particular, it was found that there was a statistically significant effect on improving plant friendliness in terms of plant friendliness and environmental sensitivity. In terms of environmental effects, it was found that there was a significant difference between the program-applied and non-programmed classes in PM10, PM2.5, and humidity. Through this study, it was confirmed that the plant education program using vertical gardens is effective in both the educational effect and the improvement of indoor air quality in the classroom. In conclusion, vertical gardening system in the elementary schools should implement for the beneficial of young generation development and back bone to the nation.

• 한국조경학회지
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• 제45권4호
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• pp.1-10
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• 2017

연구는 벽면녹화 및 벽천시스템이 없을 때를 대조구로 하여, 벽면녹화시스템 1개(Case 1), 벽면녹화시스템 2개(Case 2), 벽면녹화시스템 2개와 벽천시스템(Case 3)의 4가지 조건별 실내 온 습도 조절 및 입자상 오염물질인 PM1와 PM10 제거효과를 구명하고자 수행하였다. 실험은 충북대학교 내의 사무실에서 2015년 8월부터 9월까지 약 2개월 동안 대조구, Case 1, Case 2, Case 3 순으로 순차적으로 진행하였고, 실험기간 동안 외기온도가 비교적 일정했던 2015년 8월 17~20일(반복 실험 1), 8월 31일~9월 3일(반복 실험 2)의 데이터를 이용하여 분석하였다. 실내조경 설치에 따른 식물의 용적비는 대조구, Case 1, Case 2, Case 3이 각각 0, 0.6, 1.2, 1.4%였다. 대조구와 비교하여 Case 1, Case 2, Case 3의 평균온도는 각각 0.3~0.7, 0.7~0.9, $1.0^{\circ}C$가 감소되었으며, 평균상대습도는 각각 1.8~8.7, 9.2~14.6, 14.8~21.9%로 상승하는 경향을 보였다. 오염원 주입 후 300분이 경과하였을 때, 대조구, Case 1, Case 2, Case 3의 PM1 잔존비율은 반복 실험 1의 경우에는 각각 25.0, 22.0, 21.2, 17.3%이었으며, 반복 실험 2에서는 42.3, 28.9, 23.1, 30.9%로 나타났다. PM10 잔존비율은 반복 실험1에서는 각각 13.8, 10.8, 12.5, 9.2%이었으며, 반복 실험 2에서는 각각 24.5, 15.3, 12.6, 14.8%로 나타났다. 실내녹화 면적이 증가함에 따라 실내 온도와 PM1, PM10의 저감효과는 컸으며, 습도는 온도와 음(-)의 상관관계를 보였다. PM1과 PM10은 상대습도가 높을수록 빨리 감소되는 경향을 보였다.

• Asian Journal of Atmospheric Environment
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• 제6권2호
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• pp.73-82
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• 2012

This study was aimed to thoroughly estimate the characteristics of indoor particulate matter (PM) collected on subway platforms by the cooperative approach of semi-bulk and single particle analyses. The size-resolved PM and its number concentration were measured on the platform in a heavily traveled subway station in Fukuoka, Japan. Particle Induced X-ray Emission (PIXE) and micro-PIXE techniques were applied to the chemical analyses of semi-bulk and single particle, respectively. There was the close resemblance of timely fluctuation between PM number concentration and train service on the third basement floor (B3F) platform compared to the second basement floor (B2F) and its maximum level was marked in rush hour. Higher number counts in large particles ($>1{\mu}m$) and lower number counts in fine particles ($<1{\mu}m$) were shown on the platform compared to an above ground. PM2.5 accounted for 58.2% and 38.2 % of TSP on B3F and on B2F, respectively. The elements that were ranked at high concentration in size-resolved semi-bulk PM were Fe, Si, Ca, S, and Na. The major elements tending to have more elevated levels on B3F than B2F were Fe (4.4 times), Ca (17.3 times), and Si (46.4 times). Although concentrations were very low, Cr ($11.9ng\;m^{-3}$ on B3F, $2.4ng\;m^{-3}$ on B2F), Mn ($3.4ng\;m^{-3}$ on B3F, $0.9ng\;m^{-3}$ on B2F), and Pb ($0.6ng\;m^{-3}$ on B3F, $1.6ng\;m^{-3}$ on B2F) were detected from PM2.5. Individual PM was nearly all enriched in Fe with Si and Ca. Classifying and source profiling of the individual particles by elemental maps and particle morphology were tried and particles were presumably divided into four groups (i.e., train/rail friction, train-rail sparking, ballast/abrasive, and cement).

• 한국대기환경학회지
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• 제26권5호
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• pp.543-553
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• 2010

Almost five million citizens a day are using subways as a means of traffic communication in the Seoul metropolitan. As the subway system is typically a closed environment, indoor air pollution problems frequently occurs and passengers complain of mal-health impact. Especially $PM_{10}$ is well known as one of the major pollutants in subway indoor environments. The purpose of this study was to compare the indoor air quality in terms of $PM_{10}$ and to quantitatively compare its source contributions in a Seoul subway platform before and after installing platform screen doors (PSD). $PM_{10}$ samples were collected on the J station platform of Subway Line 7 in Seoul metropolitan area from Jun. 12, 2008 to Jan. 12, 2009. The samples collected on membrane filters using $PM_{10}$ mini-volume portable samplers were then analyzed for trace metals and soluble ions. A total of 18 chemical species (Ba, Mn, Cr, Cd, Si, Fe, Ni, Al, Cu, Pb, Ti, $Na^+$, $NH_4^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, and ${SO_4}^{2-}$) were analyzed by using an ICP-AES and an IC after performing proper pre-treatments of each sample filter. Based on the chemical information, positive matrix factorization (PMF) model was applied to identify the source of particulate matters. $PM_{10}$ for the station was characterized by three sources such as ferrous related source, soil and road dust related source, and fine secondary aerosol source. After installing PSD, the average $PM_{10}$ concentration was decreased by 20.5% during the study periods. Especially the contribution of the ferrous related source emitted during train service in a tunnel route was decreased from 59.1% to 43.8% since both platform and tunnel areas were completely blocked by screen doors. However, the contribution of the fine secondary aerosol source emitted from various outside combustion activities was increased from 14.8% to 29.9% presumably due to ill-managed ventilation system and confined platform space.

• 한국환경보건학회지
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• 제32권5호
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• pp.387-397
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• 2006

This study was performed to investigate the characteristics of indoor air quality(IAQ) in 91 public facilities from September 2004 to March 2005 in the Honam province(Chonnam, Gwangju). The measured air pollutants are $PM_{10}$, formaldehyde(HCHO), CO, $CO_{2}$ and total suspended bacteria(TSB), the maintenance standard materials of IAQ management law established by ministry of environment in Korea(MOE). We also surveyed establishment and operation of ventilation equipment. It was measured $1.2m{\sim}1.5m$ on the floor between 8 o'clock AM and 7 o'clock PM. As the result, $PM_{10}$ and CO was showed the highest concentration, $188.89{\mu}g/m^{3}$, 8.67 ppm, at the indoor parking. The concentration of HCHO was the highest in large store and steamer room. The concentration was respectively $118.70{\mu}g/m^{3}\;and\;113.21{\mu}g/m^{3}$. The concentration of $CO_{2}$ was the highest at the reading room of the library on the condition of natural ventilation. The concentration of $CO_{2}$ was 1,816 ppm and higher than the IAQ standards established by MOE. The TSB was just measured in the hospital and silver town. It was the highest at the admission room of hospital. The concentration of TSB was $766CFU/m^{3}$. The public facilities of this study were not exceed each maintenance standards except $CO_{2}$ but it was surveyed that the management will be needed about some air pollutant according to target facilities.