• Asian Journal of Atmospheric Environment
• /
• 제12권3호
• /
• pp.274-288
• /
• 2018

Quantitative data of 50 non-polar organic compounds constituting $PM_{2.5}$ were continuously collected and analyzed from June 2016 to October 2017 (approximately 17 months) at Ichihara, one of the largest industrial areas in Japan. Target non-polar organic compounds including 21 species of polycyclic aromatic hydrocarbons (PAHs), 24 species of n-alkanes and 5 species of phthalate esters(PAEs) were simultaneously measured by gas chromatography/mass spectrometry. Basically, the average concentrations of the total PAHs, n-alkanes and PAEs in each season remained nearly level, and seasonal variations were little throughout the study period. These results suggest that the emission sources, which are not influenced by the seasons, are the dominant inputs for the target organic compounds. Diagnostic ratios of PAHs, assessment of n-alkane homologue distributions, carbon preference index, and the contribution of wax n-alkanes from plants were used to estimate source apportionments. These results indicate that anthropogenic sources were the main contributor for most PAHs and n-alkanes throughout the study period. The concentrations of PAEs selected in this study were low because emission amounts of these chemicals were little within the source areas of the sampling site. To our knowledge, this study is the first attempt to simultaneously measure a high number of non-polar organic compounds in $PM_{2.5}$ collected from the ambient air of Japan, and the resultant data will provide valuable data and information for environmental researchers.

• 한국자동차공학회논문집
• /
• 제16권1호
• /
• pp.181-187
• /
• 2008

Recently, alternative fuels are drawing more attentions due to the increasing need for lower emission characteristics and fuel consumption rate in automotive engines. The GTL(gas to luquid) is the one of most favored candidates. It has higher cetane number(more than 75) and almost negligible sulphur and aromatic contents. Therefore, enhanced emission characteristics are expected even in the application in diesel engines without any modification. In this study, the cylinder pressure and heat release, emission characteristics with fuel injection timings are compared between diesel and GTL fuel in the single cylinder diesel engine. Noticeable reduction in PM, THC and CO emission are observed due to lower sulphur and aromatic contents in GTL. Also, the ignition delay decreased due to higher cetane number of GTL, which slightly decreased the amount of NOx emissions. With the retards of main injection timing, NOx decreases more for the case of GTL, while the level of THC and CO emissions still remains lower than the case of diesel. Therefore, there is much room for the control of injection timing for NOx reduction without sacrificing THC and CO emissions. With the retards of main injection timing, Small size distribution of PM became lager and there amount increased. But from all conditions, size distribution of PM for the case GTL was lower than Diesel.

• 한국대기환경학회지
• /
• 제34권2호
• /
• pp.294-305
• /
• 2018

Quantitative assessment on the impact from North Korean emissions to surface particulate matter(PM) concentration in the Seoul Metropolitan Area (SMA), South Korea is conducted using a 3-dimensional chemistry transport model. Transboundary transport of air pollutants and their precursors are important to understand regional air quality in East Asian countries. As North Korea locates in the middle of main transport pathways of Chinese pollutants, quantifiable estimation of its impact is essential for policy making in South Korean air quality management. In this study, the Community Multiscale Air Quality Modeling System is utilized to simulate regional air quality and its sensitivity, using the Comprehensive Regional Emissions inventory for Atmospheric Transport Experiment 2015 and the Clean Air Policy Support System 2013 emissions inventories for North and South Korea, respectively. Contributions were estimated by a brute force method, perturbing 50% of North and South Korean emissions. Simulations demonstrate that North Korean emissions contribute $3.89{\mu}g/m^3$ of annual surface PM concentrations in the SMA, which accounts 14.7% of the region's average. Impacts are dominant in nitrate and organic carbon (OC) concentrations, attributing almost 40% of SMA OC concentration during January and February. Clear seasonal variations are also found in North Korean emissions contribution to South Korea (and vice versa) due to seasonal characteristics of synoptic weather, especially by the change of seasonal flow patterns.

• 한국환경보건학회지
• /
• 제35권4호
• /
• pp.304-314
• /
• 2009

A new harbor as been constructing in Gadukdo. However, a lot of fugitive dust gas been often generated from construction site reclaiming sea sand, especially when the Northwester is blown strongly. It has resulted insome appeals of residents in Gadukdo. In this study, we estimated the amount of fugitive dust caused by new harbor construction using Fugitive dust formula. Also, the concentration of PM10 for recipient is predicted by AERMOD. The amount of fugitive dust is 26.56 ${\mu}g/sec{\cdot}m^2$ and 11.84 ${\mu}g/sec{\cdot}m^2$ respectively by the Fugitive dust formula. PM10 outlet concentration and the amount of fugitive dust increase according to wind velocity and directions. AERMOD is performed on the basis of weather data and the amount of fugitive dust generated with wind velocity. As a result of AERMOD, the PM10 concentration of Sunchang and Oinul are predicted over 100 ${\mu}g/m^3$. The PM10 concentration of Sunchang and Oinul are predicted over 130 ${\mu}g/m^3$ when wind velocity of northwester in winter is over 11 m/s (Air Quality for Particulate Matter (100 ${\mu}g/m^3$ for 24 hours)). Also, the measured error between AERMOD and actual measurement is lower than 5%.

• 한국산업보건학회지
• /
• 제27권4호
• /
• pp.361-370
• /
• 2017

Objectives: This study evaluated the diesel engine exhaust (DEE) exposure levels of door-to-door deliverers in Daegu from July to September. Methods: We measured exposure levels of DEE surrogates for the same door-to-door deliverers who joined the particulate matter 2.5 exposure study previously published in this journal. Black carbon(BC) concentrations were measured using real-time BC monitoring devices with 1 minute interval. $NO_2$ concentrations were monitored using passive badges. DEE exposure data were analyzed using the same characteristics and GPS information as the first study. Results: A total of 40 measurements of BC concentrations and $NO_2$ concentrations were collected during delivery of parcels. The average exposure levels to BC, and $NO_2$ were $2.23{\mu}g/m^3$ ($0.001-350.85{\mu}g/m^3$) and 21.26 ppb(3.3-61.37 ppb), respectively. Exposure levels to BC according to the day of a week and coverage areas were not significantly different(p>0.05). Delivery trucks manufactured before 2006 caused significantly higher exposure to BC than the trucks manufactured after 2006(p<0.05). Exposure levels of BC integrated for each time in residential area and roadsides were $1.96{\mu}g/m^3$ and $3.46{\mu}g/m^3$, respectively, and the difference was statistically significant(p<0.001). The Pearson correlation coefficients between the ambient $PM_{2.5}$ and BC was significant, r=0.26(p<0.01); however, the correlations between $PM_{2.5}$ and ambient $PM_{2.5}$, and between BC of DEE and $PM_{2.5}$ of DEE did not show a significant correlation Conclusions: BC and $NO_2$ exposure levels were significantly lower when door-to-door deliverers drove newer trucks. BC exposure levels of deliverers were higher in roadsides than in residential area. DEE from nearby vehicles through open windows might be the main source of BC exposure.

• 한국자동차공학회논문집
• /
• 제15권3호
• /
• pp.153-159
• /
• 2007

Nano-Particles are influenced on the environmental protection and human health. The relationships between transient vehicle operation and nano-particle emissions are not well-known, especially for diesel passenger vehicles with DPF. In this study, a diesel passenger vehicle was measured on condition of DPF regeneration and no regeneration on a chassis dynamometer test bench. The particulate matter (PM) emission from this vehicle was measured by its number, size and mass measurement. The mass of the total PM was evaluated with the standard gravimetric measurement method while the total number and size concentrations were measured on a NEDC driving cycle using Condensation Particle Counter (CPC) and EEPS. Total number concentration by CPC was $1.5{\times}10^{1l}N/km$, which was 20% of result by EEPS. This means about 80% of total particle emission is consist of volatile and small-sized particles(<22nm). During regeneration, particle emission was $6.2{\times}10^{12}N/km$, was emitted 400 times compared with the emission before regeneration. As for the particle size of $22{\sim}100nm$ was emitted mainly, showing peak value of near 40nm in size. This means regeneration decreased the mean size of particles. Regarding regeneration, PM showed no change while the particle number showed about 6 times difference between before and after regeneration. It seems that the regeneration influences on particle number emissions are related to DPF-fill state and filtration efficiency.

• 한국환경보건학회지
• /
• 제36권3호
• /
• pp.182-190
• /
• 2010

We examined the association of particulate matter with an aerodynamic diameter < $10\;{\mu}m$ ($PM_{10}$) with asthma-related hospitalization, stratified by socioeconomic status (SES), among children less than 15 years of age in Seoul, Korea, between 2003 and 2005. In addition, we estimated the reduction in the number of asthma-related hospitalizations that would result from implementing the World Health Organization (WHO) guideline. SES was defined based on data concerning health insurance premium grades, and grouped into two levels: lower-income group and control group. The lower-income group was classified as having an accumulated income which did not exceed the 50th percentile of the median income. Time-series analysis was performed to evaluate the association between $PM_{10}$ and asthma-related hospitalization. The Environmental Benefits Mapping and Analysis Program was used to analyze the impact on children's health. Based upon an increase of $10\;{\mu}g/m^3$ of $PM_{10}$, the asthma-related hospitalization risk for the lower-income group was increased by 1.78% (95% confidence intervals (CI) = 0.79-2.78%), while the risk for the control group was increased by 0.83% (95% CI = 0.34-1.32%). Attaining the WHO guideline, relative to the concentration in 2007, would result in a reduction in asthma-related hospitalizations of 18 cases per 100,000 of the children population in the lower-income group, and 7 cases in the control group. The health benefits of improved air quality for children in the lower-income group were thus 2.5 times greater than for children in the control group. Our results show that the lower-income group is disproportionately burdened with asthma-related hospitalization arising from air pollution. Therefore, biologically- and socioeconomically-disadvantaged populations should be considered in public health interventions in order to protect the children's health.

• 실내환경 및 냄새 학회지
• /
• 제17권4호
• /
• pp.337-345
• /
• 2018

In this study, we measured the concentration of Particulate Matter($PM_{10}$), Formaldehyde(HCHO), and Total Bacteria Count (TBC) at two facilities: day care centers, and postnatal care centers located in the cities of Gyeonggi, Gangwon, Jeolla and Gyeongsang from January 1, 2012 to December 31, 2015. $PM_{10}$ concentration was similar to the day care centers and postnatal care centers. HCHO concentration was the highest in the postnatal care centers. TBC concentration was the highest in the day care centers. Comparing the different cities, $PM_{10}$ concentration was the highest in Gyeonggi, HCHO concentration was the highest in Gyeonggi, and TBC concentration was the highest in Gyeonggi. As a result of HCHO's risk assessment, it was found that adults exceeded the carcinogenicity tolerance of $10^{-6}$ specified by the US EPA. This study is expected to be helpful in preventing damage to health from the contaminated indoor air at sensitive facilities, and can be used as basic data for indoor air quality management.

• 한국터널지하공간학회 논문집
• /
• 제22권5호
• /
• pp.591-610
• /
• 2020

활성탄(Activated carbon) 및 이산화티탄(TiO₂)이 혼합된 콘크리트는 질소산화물(NOx) 저감에 있어 우수한 성능을 나타내기 때문에 지하공간 및 터널 내부의 미세먼지 저감 목적으로 활용되고 있다. 환경 및 구조물 노후 영향으로 터널 내부에 설치된 미세먼지 저감 콘크리트 표면에서 손상이 발생된다. 따라서 미세먼지 저감 콘크리트의 성능 유지를 위해 손상(박리) 유무평가가 필요하다. 본 연구에서는 전기비저항 특성을 이용하여 콘크리트 박리 유무 평가를 위한 기초연구를 수행하였다. 활성탄(0~15%) 및 TiO₂ (0~25%) 혼합비(시멘트 중량 기준)가 증가함에 따라 전기비저항 값은 감소하였다. 건조 조건에서 활성탄 및 TiO₂가 혼합된 시멘트 경화시편은 일반 시멘트 경화시편보다 전기비저항 값이 최대 2.3배 감소되었다. 또한, 포화 조건(포화도 = 85~98%)에서 활성탄만 혼합된 경화시편은 일반 시멘트 경화시편보다 전기비저항 값이 최대 3.5배 감소하는 결과를 보였다. 시편 상태(건조 또는 포화)와 관계없이 활성탄(15%) 및 TiO₂ (25%)가 혼합된 미세먼지 저감 시편의 경우, 일반 시멘트 시편과 비교하여 전기비저항 값은 약 2.3~2.8배 차이를 보였다. 본 연구결과는 전기비저항을 이용하여 터널 내 미세먼지 저감 콘크리트의 박리를 평가하기 위한 기초자료로 유용하게 활용될 것으로 기대된다.

• Korean Chemical Engineering Research
• /
• 제48권2호
• /
• pp.268-274
• /
• 2010

유해대기오염물질인 중금속의 배출은 그 위해성으로 인해 엄격한 법적 규제를 하는 등 지대한 관심이 기우려지고 있다. 무연탄을 사용하는 상용 화력발전시설로부터 배출되는 중금속의 농도 및 배출특성에 대한 연구를 실시하였다. 대상 발전시설은 순환 유동층 연소로, 싸이클론, 보일러, 전기집진기 설비로 구성되었고 가스상 수은을 포함한 주요 중금속의 농도를 측정하기 위해 분진과 가스상 시료를 전기집진기(ESP) 전단과 연돌에서 측정하였다. 총 먼지량(TPM), PM-10, PM-2.5와 같은 입자상 물질의 배출량은 ESP 전단에서 각각 23,274, 9,555, $7,790mg/Sm^3$로 매우 높았으며, 이는 예측했던 바와 같이 미분탄 화력발전소보다 높은 수치였다. 그러나 ESP에 의한 먼지의 제거효율이 높기 때문에 연돌에서의 총 먼지량은 $0.16mg/Sm^3$ 정도였다. 마찬가지로 중금속 배출량 또한 ESP에서 높은 제거효율을 보였다. 입도분포와 입경 범위 별 중금속 농축 정도에 대한 데이터를 살펴볼 때 일부 금속의 농도는 작은 입경 범위에서 더 농축된 것을 보여 입자의 크기와 상관관계를 지어 볼 수 있었다. 수은의 경우 다른 금속들과 다르게 높은 휘발성 때문에 대부분이 가스 상태로 배출되며 그로 인하여 수은의 제거효율은 68% 정도로 다른 중금속들에 대한 제거효율보다 낮았다. ESP를 지나면서 수은 화학종이 원소수은에서 산화수은으로 변하는 것이 확인되었으며, 그로 인하여 습식세정탑이 설비된 다른 석탄 화력발전소에서는 원소 수은이 지배적인 데 반해 본 시설의 경우 연돌에서 총 수은의 절반 정도만 원소수은이었다.