• Journal of Digital Convergence
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• v.20 no.1
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• pp.1-13
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• 2022

This study aims to examine the trend and characteristics of newspaper articles concerned with fine particle matter. Newspaper articles since 1995 collected from Bigkinds were analyzed using text mining techniques, sentiment analysis and regression analysis. Air pollution measurement and domestic pollutants appeared frequently previously, but "China" became the keyword in the 2010s along with political action, the effects on the health, AD/PR, and domestic pollutants. Korea JoongAng Daily, Hankyoreh and Kyunghyang Shinmun have had more focused on political regulations whereas most regional daily newspapers on emission sources and reduction measures at the regional level. The results of this study are expected to be used as a reference for understanding the trend of newspaper articles. Future work includes further analysis and discussion of fine particle pollution condition and news reports in the post-COVID era.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.5
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• pp.653-660
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• 2006

Due to the stronger exhaust emission regulations and the introduction of advanced technology in Diesel engine, the specific Diesel particulate matters have decreased by about one order of magnitude since the 1980's. In recent years, particle number emissions rather than particulate mass emissions have become the subject of controversial discussions. Recent results from health studies imply that it is possible that particulate mass does not properly correlated with the variety of health effects attributed to Diesel exhaust. Concern is instead now focusing on nano-sized particles. This study has been performed for the better understanding about the Diesel nano-particle measurement and size distribution characteristics in the exhaust system of a turbo charged Diesel engine. A scanning mobility particle sizer(SMPS) system was applied to measure the particle number and size concentration of Diesel exhaust particles. As the experimental results, the number concentrations in the particle size (Dp<200 nm) were very sensitive to dilution conditions. Specially the changes in nano-particle number concentrations(Dp<50 nm) increased along the downstream of exhaust flow. Also we found the dilution conditions were influencing the condensation of SOF and $H_2O$ during dilution and cooling of hot exhaust.

• Korean Journal of Environmental Agriculture
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• v.40 no.3
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• pp.211-218
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• 2021

BACKGROUND: Fine particulate matter (PM_2.5) is produced by chemical reactions between various precursors. PM_2.5 has been found to create greater human risk than particulate matter (PM₁₀), with diameters that are generally 10 micrometers and smaller. Ammonia (NH₃) and nitrogen oxides (NOx) are the sources of secondary generation of PM_2.5. These substances generate PM_2.5 through some chemical reactions in the atmosphere. Through chemical reactions in the atmosphere, NH₃ generates PM_2.5. It is the causative agent of PM_2.5. In 2017 the annual ammonia emission recorded from the agricultural sector was 244,335 tons, which accounted for about 79.3% of the total ammonia emission in Korea in that year. To address this issue, the agricultural sector announced the inclusion of reducing fine particulate matter and ammonia emissions by 30% in its targets for the year 2022. This may be achieved through analyses of its emission characteristics by monitoring the PM_2.5 and NH₃. METHODS AND RESULTS: In this study, the PM_2.5 concentration was measured real-time (every 1 hour) by using beta radiation from the particle dust measuring device (Spirant BAM). NH₃ concentration was analyzed real-time by Cavity Ring-Down Spectroscopy (CRDS). The concentrations of ozone (O₃) and nitrogen dioxide (NO₂) were continuously measured and analyzed for the masses collected on filter papers by ultraviolet photometry and chemiluminescence. CONCLUSION: This study established air pollutant monitoring system in agricultural areas to analyze the NH₃ emission characteristics. The amount of PM_2.5 and NH₃ emission in agriculture was measured. Scientific evidence in agricultural areas was obtained by identifying the emission concentration and characteristics per season (monthly) and per hour.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.10 s.253
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• pp.973-981
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• 2006

Recently there is an increasing interest in particulate matter emission because of new emission regulations, health awareness and environmental problems. It requires to improve particulate measurement techniques as well as to reduce soot emissions from combustion systems. As mentioned above, it is demanded that reduction techniques together with measurement techniques of exhausted particulate matters in combustion systems such as vehicles. However, measurement techniques of particulate matters should be prior to reduction techniques of that because it is able to know an increase and a decrease of exhausted particulate matters when measured particulate matters. Therefore, in this study, we report the measurement of soot primary-particle size using time-resolved laser induced incandescence (TIRE-LII) technique in laminar ethylene diffusion flame. As an optical method, laser induced incandescence is one of well known methods to get information for spatial and temporal soot volume fraction and soot primary particle size. Furthermore, TIRE-LII is able to measure soot primary particle size that is decided to solve the decay ate of signal S $(t_1)$ and S $(t_2)$ at two detection time. In laminar ethylene diffusion flame, visual flame height is 40 mm from burner tip and measurement points are height of 15, 20, 27.5, 30 mm above burner tip along radial direction. As increasing the height of the flame from burne. tip, primary particle size was increased to HAB(Height Above Burner tip)=20mm, and then decreased from HAB=27.5 mm to 30 mm. This results show the growth and oxidation processes for soot particles formed by combustion.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.339-350
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• 2018

The rail wear measurements in urban underground railway have been analyzed to predict the particulate matter emission caused by rail wear which is one of the major sources of particulate matter emission for underground railway systems. From the rail profile variations measured in the interval of one and half year by dedicated rail wear measuring instrument over the commercial urban underground railway line, 'line-s' which is about 45km long, the characteristics as well as the amount of rail wear have been analyzed after dividing the whole line into about 170 section with radius of curve(R). It has been concluded that the vertical wear parameter V0 and corner wear parameter C0 have been selected to represent the wear amount of straight and curved rail respectively. The amount of rail wear as well as the particulate matter emission by rail wear over the whole line normalized by the rail length as well as the number of train has also been deduced from the relationship between the rail wear parameters and the amount of rail cross-section area.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.8
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• pp.755-760
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• 2010

In this study, we mainly focused on the PM (Particulate Matter) emission characteristics of a diesel engine. To analyze particle behavior in the tail-pipe, particle emission was measured on the engine-out (downstream of turbocharger), each upstream and downstream both of DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particulate Filter). Moreover, particle emission contours on each sampling point were constructed. The reduction efficiency of particle number concentration and mass through the DOC and DPF was studied. Parameters such as EGR (Exhaust Gas Recirculation) and the main injection timing were varied in part load conditions and evaluated using the engine-out emissions. The DMS500 (Differential Mobility Spectrometer) was used as a particle measurement instrument that can measure particle concentrations from 5 nm to 1000 nm. Nano-particles of sizes less than 30 nm were reduced by oxidation or coagulated with solid particles in the tail-pipe and DOC. The DPF has a very high filtration efficiency over all operating conditions except during natural regeneration of DPF.

• Particle and aerosol research
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• v.14 no.4
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• pp.171-180
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• 2018

To optimize the shape of the electrostatic precipitator for the removal of particulate matter in subway environments, the wind-tunnel experiments were carried out to characterize collection efficiency and ozone emission rate. As a standardized parameter, power consumption divided by the square of flow velocity, was increased, the $PM_{10}$ collection efficiency increased. If the standardized parameter is higher than 1.0 due to high power consumption or low flow velocity, increase in thickness of electrodes from 1 to 2 mm, or increase in distance of collection plates from 5 to 10 cm did not change the $PM_{10}$ collection efficiency much. Increase in thickness of high-voltage electrodes, however, can cause decrease in $PM_{10}$ collection efficiency by 28% for low power consumption and high flow velocity. The ozone emission rate decreased as distance of collection plates became wider, because the ozone emission rate per unit channel was constant, and the number of collection channels decreased as the distance of collection plates increased. When the distance of collection plates was narrow, the ozone emission rate increased with the increase of the thickness of electrodes, but the difference was negligible when the distance of collection plates was wide. It was found that the electrostatic precipitator having a thin high-voltage electrodes and a narrow distance of collection plates is advantageous. However, to increase the thickness of high-voltage electrodes, or to increase the distance of collection plates is needed, it is necessary to increase the applied voltage or reduce the flow rate to compensate reduction of the collection efficiency.

• Particle and aerosol research
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• v.20 no.1
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• pp.13-24
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• 2024

The concentrations of polycyclic aromatic hydrocarbons (PAHs) and elemental carbon (EC) in particulate matter, typical primary aerosols have decreased in Seoul between 2003 and 2018 (80% for PAHs and 85% for EC). The yearly mean benzo[a]pyrene (BaP) concentration has been lower than 1 ng/m3 since 2010-2011, the target value set by the European Union (EU) and China. A series of policies related to solid fuel and vehicle in South Korea and China should be effective in the reduction of the ambient PAHs and EC concentrations. But the emission data of PAHs and EC at both countries did not support that hypothesis. Possible causes are uncertainties in the emission inventories of primary carbonaceous aerosols in South Korea and China, although there may be a minor effect of the emissions from North Korea on the concentrations in Seoul. Thus the further policy directions against PAHs and EC such as improvements of emissions inventories and measurements, intensive regulation of non-road mobile sources and control of PAHs derivatives are discussed.

• Electronics and Telecommunications Trends
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• v.34 no.2
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• pp.83-91
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• 2019

In this article, we introduce examples and technologies relating to particulate matter (PM) reduction technology, for the purpose of reducing PM that harms health and affects the entire industry such as dust-sensitive semiconductor industry. First, the definition of PM and how it is generated is explained, including its effects on the human body. In addition, various methods for measuring PM are described, including examples of the restrictions on the operation of polluting vehicles and emission reduction devices. Finally, we describe techniques relating to the reduction and forecasting of PM.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.374-384
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• 2016

Concern about air pollution is gradually rising up in domestic and foreign, automotive and fuel researchers are trying to reduce vehicle exhaust emissions, through a lot of approaches, which consist of new engine design and innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research is proceeding by two main issues : exhaust emissions and PM particle emissions of gasoline vehicle. Exhaust emissions, non-regulated emissions and PM (particulate matter) particles of automotive are causing many problems which ambient pollution and harmful effects on the human body. The main particulate fraction of automotive exhaust emissions consists of small particles. Because of their small size, inhaled particles can easily penetrate deep into the lungs. The rough surfaces of these particles make it easier for them to combine with other toxins in the environment. Thus, the hazards of particle inhalation are increased. Based on the oxygenated fuel additive types (MTBE, Bio-ETBE, Bio-ethanol, Bio-butanol), this paper discussed the influence of oxygen contents on gasoline vehicle exhaust emissions, non-regulated emissions and nano-particle emissions. Also, this paper assessed exhaust emission characteristics at 2 type test modes. The test modes were FTP-75 and HWFET. All measurement items be verified less than the value of regulated emissions. It could be known difference increase and decrease by each measurement item depending on increase the oxygen contents.