타코나이트 광산 공정에서의 실시간 질량측정기기와 실시간 수농도의 환산에 의한 질량농도와의 연관성

정은교 ( Eun Kyo Chung ),장재길 ( Jae Kil Jang ),송세욱 ( Se Wook Song ),김정호 ( Jeongho Kim ) 한국산업보건학회 2014 한국산업보건학회지 Vol.24 No.1

Objectives: The purposes of this study are to investigate workers`` exposures to respirable particles generated in taconite mines and to compare two metric methods for mass concentrations using direct-reading instruments. Methods: Air monitorings were conducted at six mines where subjects have been exposed primarily to particulate matters in crushing, concentrating, and pelletizing processes. Air samples were collected during 4 hours of the entire work shift for similarly exposure groups(SEGs) of nine jobs(N=37). Following instruments were employed to evaluate the workplace: a nanoparticle aerosol monitor(particle size range; 10-1000 nm, unit: ㎛2/cc, Model 9000, TSI Inc.); DustTrak air monitors(PM10, PM2.5, unit: ㎎/㎥, Model 8520, TSI Inc.); a condensation particle counter(size range; 20-1000 nm, unit: #/cc, P-Trak 8525, TSI Inc.); and an optical particle counter(particle number by size range 0.3-25 ㎛, unit: #/cc, Aerotrak 9306, TSI Inc.). Results: The highest airborne concentration among SEGs was for furnace operator followed by pelletizing maintenance workers in number of particle and surface area, but not in mass concentrations. The geometric means of PM2.5 by the DustTrak and the Ptrak/Aerotrak were 0.04 mg/m3(GSD 2.52) and 0.07 mg/m3(GSD 2.60), respectively. Also, the geometric means of RPM by the DustTrak and the Ptrak/Aerotrak were 0.16 ㎎/㎥(GSD 2.24) and 0.32 ㎎/㎥(GSD 3.24), respectively. The Pearson correlation coefficient for DustTrak PM2.5 and Ptrak/Aerotrak PM2.5 was 0.56, and that of DustTrak RPM and Ptrak/Aerotrak RPM was 0.65, indicating a moderate positive association between the two sampling methods. Surface area and number concentration were highly correlated(R2 = 0.80), while PM2.5 and RPM were also statistically correlated each other(R2 = 0.79). Conclusions: The results suggest that it is possible to measure airborne particulates by mass concentrations or particle number concentrations using real-time instruments instead of using the DustTrak Aerosol monitor that monitor mass concentrations only.

전자산업 청정실의 작업환경 및 유해물질농도 평가

정은교 ( Eun Kyo Chung ),박현희 ( Hyun Hee Park ),신정아 ( Jung Ah Shin ),장재길 ( Jae Kil Jang ) 한국산업보건학회 2009 한국산업보건학회지 Vol.19 No.3

반도체 제조 근로자의 극저주파 자기장 노출 평가

정은교 ( Eun Kyo Chung ),김갑배 ( Kab Bae Kim ),정광재 ( Kwang Jae Chung ),이인섭 ( In Seop Lee ),유기호 ( Ki Ho You ),박정선 ( Jung Sun Park ) 한국산업위생학회 2012 한국산업보건학회지 Vol.22 No.1

Objectives: To compare the exposure level of extremely low frequency (ELF) magnetic fields among semiconductor workers, shipyard welders and office workers. Methods: To measure the ELF magnetic field concentration, EMDEX LITE (Enertech, USA) were used and monitored for eight hours continuously. Five companies handling the electric and magnetic field (EMF) source were investigated, which the exposure groups were classified into three groups: semiconductor workers, welders, and office workers. Welder group was chosen as a high exposed group and office group as a low exposed group. Results: The arithmetic mean (± SD) and geometric mean (GSD) of personal exposure level of semiconductor workers were 0.73 (± 1.33) μT, 0.43 (2.88) μT, respectively. The ceiling value ranged between 0.18 and 123.2 μT. Welders were exposed high with the arithmetic mean value of 3.46 (± 13.46) μT and geometric mean value of 0.45 (4.70) μT, respectively, and ceiling value range of 75.5~129.6 μT. The exposure levels of office workers were low compared to other exposed groups; the arithmetic mean 0.05 (± 0.13) μT, geometric mean 0.03 (2.38) μT and ceiling value range 0.37~3.35 μT. This study revealed statistically significant differences of the mean ELF magnetic field exposure doses among three groups (p < 0.01). Conclusions: The average ELF magnetic field exposure doses of semiconductor workers were much higher than those of office workers in control group, but were lower than those of welders in high exposure group.

내반슬 여성의 스쿼트 운동 시 발의 위치가 동적안정성에 미치는 영향

정은교 ( Eun-kyo Chung ),임비오 ( Bee-oh Lim ) 대한스포츠의학회 2018 대한스포츠의학회지 Vol.36 No.4

Purpose: The aim of this study was to investigate the effects of foot position on dynamic stability in female with genu varum. Methods: Eight females with genu varum participated in this study and performed the four squat exercise methods that foot position (-45˚, 0˚, +45˚) and 0˚ squat with band. Center of pressure (COP; anterior-posterior, medial-lateral, traveled distance, ellipse area) and ground reaction force as dynamic stability were measured using footscan system. Multivariate analysis of variance and one-way repeated analysis of variance measurement with Tukey honestly significant difference were used to identify significant differences of foot angle (-45˚, 0˚, +45˚) and 0˚ squat with band method. Results: In anterior-posterior COP displacement, -45˚ foot angle and 0˚ squat with band were significantly showed lower than +45˚ foot angle squat (p=0.006). Also, in COP traveled distance, 0˚ squat was significantly showed lower than +45˚ foot angle (p=0.019). During the descending phase, ground reaction force significantly showed in -45 foot angle was lower than other exercise methods. Conclusion: The 0˚ squat with band exercise showed higher dynamic stability and +45˚ foot angle squat exercise showed lower dynamic stability in female with genu varum.

전리방사선 노출과 관리

정은교 ( Eun Kyo Chung ),김갑배 ( Kab Bae Kim ),송세욱 ( Se Wook Song ) 한국산업보건학회 2015 한국산업보건학회지 Vol.25 No.1

Objectives: To investigate safety and health management, conditions in factories or facilities handling radiation-generating devices and radioactive isotopes were reviewed in terms of regulations of radiation safety control in Korea. Radiation exposure levels generated at those facilities were directly measured and evaluated for establishing an effective safety and health management plan. Methods: Government organizations with laws and systems of radiation safety and health were investigated and compared. There are three laws governing radiation-related employment such as occupational safety and health acts, nuclear safety acts, and medical service acts. We inspected 12 workplaces as research objects: four workplaces that manufacture and assemble semiconductor devices, three non-destructive inspection workplaces that perform inspections on radiation penetration, and five workplaces in textile and tire manufacturing. Monitoring of radiation exposure was performed through two methods. Spatial and surface monitoring using real-time radiation instruments was performed on each site handling radiation generating devices and radioactive isotopes in order to identify radiation leakage. Results: According to the occupational safety and health act, there is no legal obligation to measure ionizing radiation and set dose limits. This can cause confusion in the application of the laws, because the scopes and contents are different from each other. Surface dose rates in radiation generating devices such as implanters, thickness gages and accelerators, which were registered according to nuclear safety acts, using surveymeters, and seven of 36 facilities(19.4%) exceeded the international standards for surface radiation dose of 10 μSv/hr. Conclusions: The results showed that occupational health and safety acts require a separate provision for measuring and assessing the radiation exposure of workers performing radiation work. Like noise, ionizing radiation will also periodically be controlled by including it in the object factors of work-environment measurement.

라돈의 가이드라인 고찰 및 선량 예측

정은교 ( Eun Kyo Chung ),김갑배 ( Kab Bae Kim ),장재길 ( Jae Kil Jang ),송세욱 ( Se Wook Song ) 한국산업보건학회 (구 한국산업위생학회) 2016 한국산업보건학회지 Vol.26 No.2

Objectives: To review reference levels by the international and domestic management and provide the basis for setting occupational exposure limits(OELs) of radon in Korea Methods: Government``s organizations with laws and systems for monitoring radon exposure were investigated and compared. There are five laws governing Indoor Air Quality(IAQ) control such as Occupational Safety and Health Act, Indoor Air Quality Control in Public Use Facilities, Etc. Act, School Health Act, Public Health Control Act and Parking Lot Act in Korea. It was surveyed that a total of 32 countries including 24 countries in the European Union(EU), six countries in Asian and two countries in North America setting the reference levels for radon in the world. Results: In Korea, there are set guidelines for radon in the Ministry of Environment and the Ministry of Education. Reference levels of radon for existing dwellings were 150~400 ㏃/㎥ for Western European countries, and 200~1,500 ㏃/㎥ in Eastern European countries. Approximately 67% of those EU countries were set up 400 ㏃/㎥ to the standards for existing dwellings. EU countries such as Luxembourg, Finland, Norway, Sweden and Russia had adopted mandatory level for radon. Radon guidelines for new dwellings were set more strictly reference level(200 ㏃/㎥) than existing dwellings. Conclusions: International organizations such as ICRP, UNSCEAR and NCRP, etc. had recommended the guidelines for radon. It was calculated the relation of the dose conversion factors with the annual effective doses. the OELs of radon suggest to need to establish 150 ㏃/㎥ for office room and 400~1,000 ㏃/㎥ for the workplace

인산석고 취급공정에서의 라돈농도 및 유효선량 수준 평가

정은교 ( Eun Kyo Chung ),장재길 ( Jae Kil Jang ),김종규 ( Jong Kyu Kim ),김준범 ( Joon Beom Kim ),권지운 ( Jiwoon Kwon ) 한국산업보건학회 (구 한국산업위생학회) 2018 한국산업보건학회지 Vol.28 No.3

Objectives: To monitor the radon concentration level in plants that handle phosphorus rock and produce gypsum board and cement, and evaluate the effective dose considering the effect of radon exposure on the human body. Methods: Airborne radon concentrations were measured using alpha-track radon detectors (α-track, Rn-tech Co., Korea) and continuous monitors (Radon Sentinel 1030, Sun Nuclear Co., USA). Radon concentrations in the air were converted to radon doses using the following equation to evaluate the human effects due to radon. H (m㏜/yr) = Radon gas concentration x Equilibrium factor x Occupancy factor x Dose conversion factor. The International Commission on Radiological Protection (ICRP) used 8 n㏜/(㏃·hr/㎥) as the dose conversion factor in 2010, but raised it by a factor of four to 33 n㏜/(㏃·hr/㎥) in 2017. Results: Radon concentrations and effective doses in fertilizer manufacturing process averaged 14.3 (2.7) ㏃/㎥ (2.0-551.3 ㏃/㎥), 0.11-0.54 m㏜/yr depending on the advisory authority and recommendation year, respectively. Radon concentrations in the gypsum-board manufacturing process averaged 14.9 ㏃/㎥ at material storage, 11.4 ㏃/㎥ at burnability, 8.1 ㏃/㎥ at mixing, 10.0 ㏃/㎥ at forming, 8.9 ㏃/㎥ at drying, 14.7 ㏃/㎥ at cutting, and 10.5 ㏃/㎥ at shipment. It was low because it did not use phosphate gypsum. Radon concentrations and effective doses in the cement manufacturing process were 23.2 ㏃/㎥ in the stowage area, 20.2 ㏃/㎥ in the hopper, 16.8 ㏃/㎥ in the feeder and 11.9 ㏃/㎥ in the cement mill, marking 0.12-0.63 m㏜/yr, respectively. Conclusions: Workers handling phosphorous gypsum directly or indirectly can be assessed as exposed to an annual average radon dose of 0.16 to 2.04 mSv or 0.010 to 0.102 WLM (Working Level Month).

필라테스 서비스품질이 가치, 만족 및 재이용에 미치는 관계 분석

정은교(Chung, Eun-Kyo),황인선(Hwang, In-Sun),이상일(Lee, Sang-Il) 한국체육과학회 2020 한국체육과학회지 Vol.29 No.6

The purpose of this study is to identify the effect of service quality on the value, satisfaction and reuse for Pilates users. Based on this, we are to provide the basic operational data to establish a marketing strategy that leads to reuse by service quality affecting value and satisfaction. In order to secure the basic data of the study, participants in the Pilates Centers in Seoul and Gyeonggi-do were selected as the population from February 25 to March 25, 2020 and 328 questionnaires were used for the actual analysis. The collected data was analyzed using the statistical program SPSS 26.0 Version, and frequency analysis to identify general characteristics, exploratory factor analysis to verify construct validity, reliability analysis (using aplha value), correlation analysis among variables, multiple regression analysis for impact analysis and simple regression analysis were used, and the following results were derived: First, Pilates service quality was found to have an impact on value. Second, Pilates service quality was found to affect satisfaction. Third, Pilates service quality partially affected reuse. Fourth it was found that the value of Pilates users affects reuse. Fifth, it was found that the satisfaction of Pilates users affects reuse.

석유 및 석탄화학의 대보수작업중 벤젠노출 특성 비교

정은교 ( Eun Kyo Chung ),유계묵,신정아 ( Jung Ah Shin ),권지운 ( Ji Woon Kwon ),박현희 ( Hyun Hee Park ),정광재 ( Kwang Jae Chung ),이인섭 ( Seop In Lee ),강성규 ( Seong Kyu Kang ),류향우 ( Hyang Woo Ryu ),김영선 ( Yong Sun Kim ) 한국산업위생학회 2010 한국산업보건학회지 Vol.20 No.3

This study was conducted to investigate the benzene exposure levels in coal chemical and petrochemical refining industries during BTX turnaround (TA) processes where benzene was being produced. Three companies producing benzene were selected, one coal chemical and two petrochemical industries. TA processes were classified into three stages: shut down, maintenance, and start up. Data was analyzed by classifying the refining method into 2 groups (Petrochemistry, Coal chemistry) for 823 workers. Comparing the data from petrochemical industries with data from a coal chemical refining industry, while benzene concentration levels of long-term samples during TA were not statistically different (p>0.05), those levels of short-term samples were significantly different (p<0.001). About 4.79 % of data in petrochemical industries exceed the occupational exposure limits (OELs) of benzene, 1 ppm. In a coal refining methods, about 15.7% exceeded the benzene OELs. The benzene concentrations in maintenance and start up stage of TA for petrochemical refineries were higher than those in a coal chemical refinery (p<0.01). These findings suggest that the coal chemical refining site requires more stringent work practice controls compare to petrochemical refining sites during TA processes. Personal protective equipments including organic respirators should be used by TA workers to protect them from benzene over-exposure.

일부 제조업 사업장의 사무 및 공장동에서의 라돈농도 수준 및 유효선량 평가

정은교 ( Eun Kyo Chung ),김기웅 ( Ki Woong Kim ) 한국산업보건학회 (구 한국산업위생학회) 2017 한국산업보건학회지 Vol.27 No.1

Objectives: Radon may be second only to smoking as a cause of lung cancer. Radon is a colorless, tasteless radioactive gas that is formed via the radioactive decay of radium. Therefore, radon levels can build up based on the amount of radium contained in construction materials such as phospho-gypsum board or when ventilation rates are low. This study provides our findings from evaluation of radon gas at facilities and offices in an industrial complex. Methods: We evaluated the office rooms and processes of 12 manufacturing factories from May 14, 2014 to September 23, 2014. Short-term data were measured by using real-time monitoring detectors(Model 1030, Sun Nuclear Co., USA) indoors in the office buildings. The radon measurements were recorded at 30-minute intervals over approximately 48 hours. The limit of detection of this instrument is 3.7 ㏃/㎥. Also, long-term data were measured by using α-track radon detectors(α-track, Rn-tech Co., Korea) in the office and factory buildings. Our detectors were exposed for over 90 days, resulting in a minimum detectable concentration of 7.4 ㏃/㎥. Detectors were placed 150-220 cm above the floor. Results: Radon concentrations averaged 20.6 ± 17.0 ㏃/㎥(3.7-115.8 ㏃/㎥) in the overall area. The monthly mean concentration of radon by building materials were in the order of gypsum>concrete>cement. Radon concentrations were measured using α-track in parallel with direct-reading radon detectors and the two metric methods for radon monitoring were compared. A t-test for the two sampling methods showed that there is no difference between the average radon concentrations(p<0.05). Most of the office buildings did not have central air-conditioning, but several rooms had window- or ceiling-mounted units. Employees could also open windows. The first, second and third floors were used mainly for office work. Conclusions: Radon levels measured during this assessment in the office rooms of buildings and processes in factories were well below the ICRP reference level of 1,000 ㏃/㎥ for workplaces and also below the lower USEPA residential guideline of 148 ㏃/ ㎥. The range of indoor annual effective dose due to radon exposure for workers working in the office and factory buildings was 0.01 to 1.45 m㏜/yr. Construction materials such as phospho-gypsum board, concrete and cement were the main emission sources for workers` exposure.