나노물질의 측정전략의 주요 쟁점

윤충식,Yoon, Chung-Sik 한국환경보건학회 2011 한국환경보건학회지 Vol.37 No.1

The growing interest in nanotechnology has resulted in increasing concern and a number of published environmental and workplace measurements for assessing occupational exposure to engineered nanomaterials. However, the amount of previous exposure data remains limited. Furthermore the data available was collected with extensive variation in terms of exposure measurement strategy, which limits the ability to pool the data in the future. In response, this paper reviewed several pertinent issues related to exposure measurement strategy to suggest a harmonized measurement strategy which would make exposure data more useful in the future, e.g. correlation between exposure metrics, relationship between activity and exposure, task-based or shift-based assessment, background concentration, limitation of personal exposure monitoring and other determinants of exposure/modeling. An improved sampling strategy for nanomaterial exposure assessment should be considered in order to maximize the use of the data from various real time monitoring instruments.

플럭스 코어드 아크 용접 공정에서의 흄 형성량에 관한 연구

윤충식,백남원,Yoon, Chung-Sik,Paik, Nam-Won 한국환경보건학회 1999 한국환경보건학회지 Vol.25 No.3

A study was conducted for the effects of input energy on fume formation ratios based on electrode(FFR$_{electrode}(g/kg_{electrode})),\;deposited\;metal(FFR_{weld}(g/kg_{weld}))\;and\;slag(FFR_{slag}(g/kg_{slag}))\;at\;CO_2$ flux cored arc welding on stainless steel. Experiments were run in well designed welding fume box. Six types of flux cored wires were used and three levels of current and voltages were given. The measured values of $FFR_{electrode},\;FFR_{weld},\;FFR_{slag}\;are\;7.90{\pm}1.47\;g/kg_{electrode},\;9.18{\pm}1.65\;g/kg_{\electrode},\;71.8{\pm}24.2\;g/kg_{slag}$ respectively. Fume formation ratios are not increased dramatically by input energy because of simultaneous increasing of melted electrodes, deposited metal and slag. The results indicate that the test of fume formation ratios in the research on production of low fume welding wire can be run at the fixed condition of input energy rather than various condition.

유아교육시설의 표면 및 공기 중 납 농도 평가

윤충식,백도현,Yoon, Chung-Sik,Paik, Do-Hyeon 한국환경보건학회 2006 한국환경보건학회지 Vol.32 No.1

This study was performed to investigate airborne lead concentration and surface lead contents in preschool facilities. Arithmetic mean of indoor lead concentration in urban area was $44.7\;ng/m^3$ (Geometric mean $32.1\;ng/m^3$) whereas outdoor concentration was $39.5\;ng/m^3$ (GM $22.8\;ng/m^3$). In rural area, airborne lead concentrations were $14.2\;ng/m^3\;(GM\;7.9 ng/m^3),\;12.6\;ng/m^3\;(GM\;5.6 ng/m^3)$, respectively. There is statistical significance of the lead concentrations among the locations of preschool facilities. About $37\%$ of qualitative lead check samples was positive and mainly was found in lead based paint. Though lead concentrations on the floor and window sill were well below the US EPA and HUD standard (floor $40\;{\mu}g/ft^2\;(4.3\;{\mu}g/100\;cm^2)$, window sill $250\;{\mu}g/ft^2\;(26.9\;{\mu}g/100\;cm^2)$, respectively), there were much samples which exceed the standard, i.e., $29\%$ of surface wall, $20\%$ of the desk and chair, $100\%$ of painted wood box of tested samples. In view of our study and hazard of lead to children, we recommended that the contents of lead in preschool facilities should be lowered as possible.

석면과 건강에 대한 이슈

윤충식,Yoon, Chung-Sik 한국환경보건학회 2009 한국환경보건학회지 Vol.35 No.5

Asbestos is a commercial term of natural occurring silicated minerals and forms long, thin fibers. Chrysotile, the serpentine asbestos, accounts for most use in commercial use. Asbestos is well known health hazard material and it is proved that inhalation of asbestos fibers leads to increased risk of developing several diseases such as lung cancer, mesothelioma, asbestosis. In these days, people most at risk for exposure are maintenance and construction workers and general citizens who are working on and close to the work area at which asbestos containing material is disturbing. Non asbestiform, though its chemical composition is same with regulated asbestos, is known to be less hazardous than asbestiform. Exposure guideline, 0.01 f/ml, is not safe level in terms of health risk. It is reasonable to take preventable action when asbestos is suspicious. In Korea, it is necessary to clarify the concept between hazard and risk, to differentiate asbestiform from non asbestiform, to make regulations for compensation for asbestos related patients, to manage future exposure for general citizens.

유아교육시설의 위치 및 실내${\cdot}$실외에 따른 포름알데히드 농도 변화

윤충식,정지연,이광용,박동욱,박두용,Yoon , Chung-Sik,Jeong , Jee-Yeon,Yi , Gwang-Yong,Park , Dong-Uk,Park , Doo-Yong 한국환경보건학회 2004 한국환경보건학회지 Vol.30 No.3

This study was performed to investigate airborne formaldehyde concentration in preschool facilities. Arithmetic mean of indoor formaldehyde concentration in urban area was 34.9 ppb(Geometric mean 24.4 ppb) whereas outdoor concentration was 21.5 ppb(GM 11.9 ppb). In rural area, formaldehyde concentrations were 36.4 ppb(GM 28.7 ppb), 4.1 ppb(GM 4.1 ppb), respectively. There is no statistical significance between the formaldehyde concentrations of urban classrooms and those of rural area. We verified that the distribution of airborne formaldehyde concentration was log-normal characteristic using Shapiro and Wilk test. The 6.7% of urban indoor samples was exceeded the domestic standard limit of indoor air quality. From our study and other study, we concluded that the major emission sources of formaldehyde in preschool facilities was in indoor rather than outdoor.

유아교육시설의 공기중 벤젠 및 휘발성 유기화합물 농도

윤충식 ( Chung Sik Yoon ),박동욱 ( Dong Uk Park ),박두용 ( Doo Yong Park ) 한국산업보건학회 2004 한국산업보건학회지 Vol.14 No.2

스테인레스 강에 대한 플럭스 코어드 아크 용접공정에서의 흄 발생량 및 입자 크기 분포에 관한 연구

윤충식(Chung Sik Yoon),백남원(Nam Won Paik) 한국환경보건학회 1999 한국환경보건학회지 Vol.25 No.2

A study was conducted for the effects of currents and voltages on the fume generation rates at CO₂ flux cored arc welding on stainless steel. Fume size distributions were also studied. Experiments were run in well designed welding fume box. Six types of flux cored wires were used and three levels of currents and voltages were given. Fume generation rates of domestic flux cored wires are 0.2-0.3 g/min at the lowest input energy and 0.81~0.85 g/min at the highest input energy tested. Fume generation rates could be related to the welding current with secondary power function and to the input energy with primary power function. Flux cored wires, when melted by arc, transfered into the deposited metal(82 ~92% ), slag(9~13% ), spatter(l~6% ), and fume(0.5~1 % ) respectively. Fulx cored welding fumes are all respirable particulate mass.

새 국제표준규격에 의한 수용성 유해금속의 평가

윤충식 ( Chung Sik Yoon ) 한국산업위생학회 2003 한국산업보건학회지 Vol.13 No.3

This study was performed to investigate the total (insoluble + soluble) metal contents and soluble metal contents in flux cored arc welding fumes. A well designed fume collection chamber for welding operations was used for flux-cored arc welding with CO2gas. Nine different products of 1.2 mm diameter flux-cored wires, five of which were for stainless steel welding applications and the others were for non-stainless welding. Ashing for total metal compositions were treated by NIOSH 7300 method and soluble metals were extracted by newly developed ISO 15202-2(Annex B). Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) was used to analyze 13 different metal components. The contents of all metals were 47.6% in the non-stainless welding fumes whereas 36.4% in the stainless welding fumes. But the soluble contents of all metals were higher in stainless welding fume than in non-stainless welding fumes(15.% vs 8.3%). The reason that soluble fractions are higher in stainless welding fumes is that there are high levels of potassium and sodium, which contribute other metals to be solubles. Hexavalent chromium, A known human carcinogen, can easily be soluble by combining with potassium and sodium. Total chromium content in stainless welding fumes were 3.8 (2.8-5.2)% and soluble content was 0.8(0.4-1.2)%. So, the soluble fraction of chromium was 21.3% in stainless flux cored arc welding fumes. The content of aluminum was exceptionally high in self-shielded flux cored wire fume(product `D`). The reason is that aluminum is added as a de-gassing agent that protect the melting part from the nitrogen and oxygen. It was found that soluble chromium concentration should be evaluated for stainless flux cored arc welding. This study revealed that how to use the fume concentration and/or total(insoluble + soluble) metal concentration to estimate soluble concentration of occupational exposure limit designated metals. The metal compositions of flux cored arc welding fumes were similar to those of shielded metal arc welding whereas welding method of flux cored arc welding were similar to that of metal gas arc welding(MIG or MAG), which were mainly explained by flux existed in both flux cored arc welding and shielded metal arc welding.

[산업보건] 초음파 전처리에 의한 용접 흄 중 6가 크롬의 분석

윤충식(Chung-Sik Yoon),백남원(Nam-Won Paik),김정한(Jeong-Han Kim),박동욱(Dong-Uk Park),최상준(Sang-Jun Choi),김신범(Shin-Bum Kim),채현병(Hyun-Byung Chae) 한국분석과학회 1999 분석과학 Vol.12 No.5

스테인레스 강 용접중 발생하는 망간의 발생량 및 함량변화에 관한 연구

윤충식 ( Chung Sik Yoon ),김정한 ( Jeong Han Kim ) 한국산업위생학회 2006 한국산업보건학회지 Vol.16 No.3

Manganese has a role as both toxic and essential in humans. Manganese is also an essential component in the welding because it increases the hardness and strength, prevents steel from cracking of welding part and acts as a deoxidizing agent to form a stable weld. In this study, manganese generation rate and its content was determined in flux cored arc welding on stainless steel. Domestic two products and foreign four products of flux cored wires were tested in the well designed fume generation chamber as a function of input power. Welding fume was measured by gravimetric method and metal manganese was determined by inductively coupled plasma-atomic emission spectrophotometer. The outer shell of the flux cored wire tube and inner flux were analyzed by scanning electron microscopy to determine their metal compositions. Manganese generation rate(FGRmn) was increased as the input power increased. It was 16.3 ㎎/min at the low input power, 38.1 ㎎/min at the optimal input power, and up to 55.4 ㎎/min at the high input power. This means that FGRmn is increased at the work place if welder raise the current and/or voltage for the high productivity. The slope coefficient of FGRmn was smaller than that of the generation rate of total fume(FGR). Also, the correlation coefficient of FGRmn was 0.65 whereas that of FGR is 0.91. FGRmn was equal or higher in the domestic products than that of the foreign products although FGR was similar. From the electron microscopic analytical data, we concluded that outer shell of the wire was composed mainly of iron, chromium, nickel and less than 1.2 % of manganese. There are many metal ingredients such as iron, silica, manganese, zirconium, titanium, nickel, potassium, and aluminum in the inner flux but they were not homogeneous. It was found that both FGRmn and content of manganese was higher and more varied in domestic flux cored wires than those of foreign products. To reduce worker exposure to fumes and hazardous component at the source, further research is needed to develop new welding filler materials that improve the quality of flux cored wire in respect to these points. Welder should keep in mind that the FGR, FGRmn and probably the generation rate of other hazardous metals were increased as the input power increase for the high productivity.