• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.26 no.4
• /
• pp.411-417
• /
• 2016

Objectives: The aims of this study were to determine the indoor level of environmental tobacco smoke (ETS) and to assess the implementation rate of smoke-free laws at hospitality venues around a university campus by measuring particulate matter smaller than $2.5{\mu}m$ ($PM_{2.5}$) as an indicator of ETS. Materials and Methods: We measured indoor $PM_{2.5}$ concentrations at 20 PC game rooms, 20 pubs, and 20 billiards halls using Sidepak AM510, a direct reading portable real time monitor, from October to December 2015. Results: Smoking was observed in 65% of the PC game rooms, 10% of pubs, and 85% of billiards halls. The average $PM_{2.5}$ concentrations were $98.2{\mu}g/m^3$, $29.0{\mu}g/m^3$, and $134.2{\mu}g/m^3$ at PC game rooms, pubs, and billiards halls, respectively. $PM_{2.5}$ concentrations in PC game rooms and billiards halls were 2 to 2.7 times higher than the 24-hour exposure standard for outdoor $PM_{2.5}$ ($50{\mu}g/m^3$) by the Ministry of Environment. Conclusions: Although a smoking ban has been implemented for PC rooms and pubs, smoking is still taking place in many of these places. More stringent legal action is required for successfully protecting patrons and workers from secondhand smoke exposure. A ban on smoking in billiards halls should be introduced as quickly as possible.

• Economic and Environmental Geology
• /
• v.30 no.4
• /
• pp.341-352
• /
• 1997

Retention ponds have been dug along some of the motorways in France to minimize environmental pollution by keeping pollutants from spreading over the surrounding area. In order to study heavy metal pollution and diagenetic behaviour of sediments, eight core samples were collected from the bottom of a retention pond located along the A-71 motorway in Sologne. The metal concentrations in interstitial waters and extractable metal concentrations in sediment layers using sequential chemical extraction method were determined. The depth distributions of Pb, Zn and Cd concentrations in interstitial water and particulate sediments were studied, and distribution coefficients (KD) were also determined to investigate the environmental mobility of these elements. In addition. the index of geoaccumulation and the Fe-normalized enrichment factor were calculated to differentiate the natural accumulation from the anthropogenic pollution. The vertical concentration profiles of heavy metals in core sediments indicate that surface enrichments (0~2 cm) of Pb, Zn, Cd and organic carbon were always observed at each core sample, due to the early diagenesis. However, the major factor contributing to the accumulation of Cd at the sediment surface is attributed to the dissolution of Cd from polluted roadside soil during periods of rainstorms and its subsequent redeposition on the sediment surface after being carried to the retention pond. A comparison of the KD values indiactes that a decrease in the KD values for Pb and Zn was observed with depth while KD values for Cd increase. According to the KD values. the relative mobility of studied metals was determined as following: Mn>Zn>Cd>Pb, for the upper layer, and Mn>Cd>Zn>Pb, for the lower layers.

• Journal of the Korean Ceramic Society
• /
• v.53 no.6
• /
• pp.659-664
• /
• 2016

Ash deposition of heat exchange boiler, caused mainly by accumulation of particulate matter, reduces heat transfer of the boiler system. Heat and mass transfer through porous media such as ash deposits mainly depend on the microstructure of deposited ash. Therefore, in this study, we investigated microstructural and thermal properties of the ash deposited on the boiler tube. Samples for this research were obtained from the fuel economizer tube in an industrial waste incinerator. To characterize microstructures of the ash deposit samples, scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD) and BET analysis were employed. The results revealed that it had a porous structure with small particles mostly of less than a few micrometers; the contents of Ca and S were 19.3, 22.6% and 18.5, 18.7%, respectively. Also, the results showed that it consisted mainly of anhydrite ($CaSO_4$) crystals. - The thermal conductivities of the ash deposit sample obtained from the economizer tube in industrial waste incinerator were measured to be 0.63 and 0.54 W/mK at $200^{\circ}C$, which were about 100 times less than the thermal conductivity (61.32 W/mK) of the boiler tube itself, indicating that ash deposition on the boiler tube was closely related to a decrease in boiler heat transfer.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.967-972
• /
• 2004

The role of transfer films formed during sliding of polymer composites against steel counterfaces was studied in terms of the tribological behaviors of composites. Four kinds of composites were included in this study: (1) unfilled PPS, (2) PPS+2%CuO, (3) PPS+2%CuO+5% carbon fiber (CF), and (4) PPS+2%CuO+15%Kevlar. The filler material CuO was in nanoscale particulate form and the reinforcing material was in the form of short fibers. The composites were prepared by compression molding at $310^{\circ}C$ and sliding tests were run in the pin-on-disk sliding configuration. The counterface was made of tool steel hardened to 55-60 HRC and finished to a surface roughness of 0.09-0.10 ${\mu}m$ Ra. Wear tests were run for 6 hrs at the sliding speed of 1 m/s and contact pressure of 0.65 MPa. Transfer films formed on the counterfaces during sliding were investigated using AFM and SEM. The results showed that as the transfer film became smooth and uniform, wear rate decreased. PPS+2%CuO+15%Kevlar composite showed the lowest steady state wear rate in this study and its transfer film showed the smoothest and the most uniform characteristics. The examination of worn surfaces of PPS+2%CuO composite using X-ray area scanning (dot mapping) showed back-transfer of steel counterface material to the polymer pin surface. This behavior is believed to strengthen the polymer pin surface during sliding thereby contributing to the decrease in wear rate.

• Journal of Radiation Protection and Research
• /
• v.34 no.4
• /
• pp.195-200
• /
• 2009

effluents to the environment. The activity of carbon-14, one of the radioactive effluents, in the environment is already high level and its effect on radiation exposure to the public and the environment is insignificant; thus, NPPs did not perform the carbon-14 monitoring in effluents in the past. By the way, effluents of noble gas and particulate radioactive materials originated from nuclear fuels has been continuously reduced due to both the advancement of manufacturing and integrity technology for nuclear fuels and the improvement of operation methods of NPPs. Futhermore, the portion of dose assessment by tritium and carbon-14 to the public has been relatively increased because the lower limit of detection for low-energy beta sources, such as tritium and carbon-14, is low due to the advancement of radiation detection technology. In this paper, the technical background for carbon-14 monitoring in nuclear facilities was investigated using United States technical reports and papers. This paper also reviews whether carbon-14 monitoring is necessary or not based on the investigated documents.

• Journal of Korean Society for Atmospheric Environment
• /
• v.27 no.4
• /
• pp.426-435
• /
• 2011

In this study, PM emission factors for commercial meat cooking were developed by the experiment using the similar restaurant model. The commercial material types of meat cooking were beef, pork and duck. And meat cooking materials were classified with marinated and raw cooking methods. The marinated and raw cooking methods were flat griddle (LPG) and under fired charbroiling grill. As a results, $PM_{10}$ emission factors for underfired pork cooking was estimated as 7.39 g/kg-meat which was the highest value in this study. The emission factors of under fired charbroiling grill method were higher than that of flat griddle method regardless of meat cooking material types and marinated meat. The particle size distribution of meat cooking was 0.23~5 ${\mu}m$ and median diameter was 2~2.5 ${\mu}m$.

• Korean Journal of Environmental Biology
• /
• v.36 no.4
• /
• pp.665-671
• /
• 2018

This paper represents an investigation into the pattern of carbon transportation and composition on an open estuary in the transition zone between the river and marine environment in Tamjin River where stream water flows into the Gangjin Bay. To conduct the study, seven plots were established along an environmental gradient from river and estuary to the ocean. Surface water samples were collected thrice during the summer rainfalls and non-flooding seasons in 2017. The samples were then measured for the concentrations of dissolved organic carbon ([DOC]), particulate organic carbon ([POC]) and dissolved inorganic carbon ([DIC]). An analysis of the results showed that [POC] did not increase in the river even during the summer rainfall. However, [DOC] increased resulting in a higher [DOC]:[POC] ratios for the non-flooding season compared to summer rainfall events. On the other hand, the marine site of the estuary bay showed the highest [DIC] which was stable relative to those of river sites. The results suggest that in an open estuary zone, river and ocean supplied the open estuary zone with different types of carbon materials; mainly DOC supplied from the river and DIC sourced from the ocean.

• Particle and aerosol research
• /
• v.18 no.3
• /
• pp.79-86
• /
• 2022

Many commercial air purifiers currently have deployed granular activated carbon (GAC) filters for removing volatile organic compounds in the indoor air. GACs are generally used to remove gaseous contaminants in the air through adsorption by the inner surfaces of pores. In addition, airborne particles can be also filtered by the surface adsorption of the GACs, which can improve the life-time of the particulate filters. In this study, the filtration efficiency of GACs to ultrafine particles through surface adsorption was investigated at different volume flow rates by deploying a continuous particle filtration system. The polydisperse sodium chloride (NaCl) particles were generated by a set of an atomizer and a diffusion dryer, and then mixed with particle-free air at different volume flow rates. The penetration of ultrafine particles and pressure drop for each experimental condition were measured to figure out the effect of the volume flow rate on the surface adsoprtion of the GACs to particles, ~ 2 mm. The particle filtration efficiency of the GACs decreased as the volume flow rate increased from 4 to 14 lpm. However, the 5 times thicker GAC filter layer decreased the penetration of ultraparticles than a preious study. The filtration efficiency of the single granule was also higher than the previous result in the literature with smaller granule filter materials.

• Journal of Environmental Science International
• /
• v.31 no.12
• /
• pp.1079-1087
• /
• 2022

This study investigated the effect of volcanic materials that erupted from the Nishinoshima volcano, Japan, 1,300 km southeast of the Busan area at the end of July 2020, on the fine particle concentration in the Busan area. Backward trajectory analysis from the HYSPLIT model showed that the air parcel from the Nishinoshima volcano turned clockwise along the edge of the North Pacific high pressure and reached the Busan area. From August 4 to August 5, 2020, the concentration of PM₁₀ and PM_2.5 in Busan started to increase rapidly from 1000 LST on August 4, and showed a high concentration for approximately 13 hours until 2400 LST. The PM_2.5/PM₁₀ ratio showed a relatively high value of 0.7 or more, and the SO₂ concentration also showed a high value at the time when the PM₁₀ and PM_2.5 concentrations were relatively high. The SO₄^2- concentration in PM_2.5 in Busan showed a similar trend to the change in PM₁₀ and PM_2.5 concentrations. It rose sharply from 1300 LST on August 4, at the time where it was expected to have been affected by the Nishinoshima Volcano. This study has shown that the occurrence of high concentration fine particle in Busan in summer has the potential to affect Korea not only due to anthropogenic factors but also from natural causes such as volcanic eruptions in Japan.

• Journal of The Geomorphological Association of Korea
• /
• v.26 no.4
• /
• pp.1-20
• /
• 2019

In order to establish appropriate policy to control sediment-associated problems, it is necessary to identify the physical characteristics of the reservoir sediments in particulate form in the Yeongsan River. Two time-integrated suspended sediment samplers were installed at Seungchon and Juksan weir on the upper and middle Yeongsan River in July 2012. Reservoir sediment samples were obtained at monthly intervals until October 2014. During the monitoring period, a total of 38 sediment samples were obtained and analyzed. Seasonal trends of suspended sedimentation rates and grain size distributions were examined based on variations in precipitation and discharge fluctuations. Moreover, stream flow characteristics, which has a great influence on the physical characteristics of the river sediment, was analyzed using flow duration curve for the period 2003-2019 at Naju gauging station. Sedimentation rates during summer, when heavy rainfall was concentrated due to the monsoonal front and typhoon, were very high, indicating the positive relationship between sediment concentration and discharge. Particle size analysis of the collected sediment showed that coarse silt and very fine sand-sized sediment dominated most of the Seungchon weir sediment. On the other hand, medium silt-sized sediment dominated the downstream Juksan weir except for a few summer samples. These results implied that the physical characteristics of the suspended sediment are determined not only due to flow fluctuations, but also with regard to the antecedent rainfall conditions, hillslope-channel connectivity, and the supply of materials from various contributing regions. This information about flow characteristics and temporal variations in reservoir sediment can be used for safe management of the weir and discussing the issues on the dismantling of the weirs.