버스 정비 작업자에 대한 석면 및 디젤 엔진 배출물질 노출 평가

이나루 ( Naroo Lee ),이광용 ( Gwangyong Yi ) 한국산업보건학회 (구 한국산업위생학회) 2016 한국산업보건학회지 Vol.26 No.2

Objectives: Lung cancer occurred with worker working in an urban bus garage. A survey was conducted to investigate whether lung cancer had causal relationship with work. Exposure to asbestos and diesel engine exhaust were suspected. Methods: Airborne asbestos was sampled on membrane filter and analyzed using phase-contrast microscopy. Airborne diesel exhaust was sampled using quartz filter and analyzed with thermal-optical analyzer. Polynuclear aromatic hydrocarbons was sampled using PTFE filter and XAD-2 tube and analyzed with gas chromatography-mass selective detector. Results: Airborne asbestos concentration was under 0.01 fiber/cc. Worker who warmed up an engine of urban bus for 2 hours was exposed to elemental carbon concentration, 15.5㎍/㎥. Only naphtalene among polynuclear aromatic hydrocarbons was detected. Conclusions: It was difficult to conclude about worker exposure to asbestos because working hour related asbestos was too short. In reviewing papers, the exposure to asbestos over 0.01 fiber/cc during exchange brake lining was found. It was identified that worker``s occupational exposure to diesel exhaust based on elemental carbon was higher than the other occupational exposure to diesel exhaust

국내에서 유통되는 활성탄을 이용한 벤젠, 톨루엔, 아세톤 및 노말 헥산의 등온흡착용량 평가 연구

이나루 ( Naroo Lee ),이광용 ( Gwang Yong Yi ),박두용 ( Dooyong Park ) 한국산업보건학회 2014 한국산업보건학회지 Vol.24 No.2

Objectives: To develop domestic charcoal tubes with good adsorption capacity, breakthrough experiments were performed on four types of activated charcoal. Materials: The adsorption capacity and the adsorption rate were determined using a modified Wheeler equation after the breakthrough experiment. For four types of charcoal (J, K, S and SKC Inc. 226-01), 100 ㎎ were used in the breakthrough experiment. The test was done on benzene, toluene, n-hexane, and acetone in a dynamic chamber. Results: K charcoal had the greatest surface area and the highest micropore volume. J charcoal had a similar surface area and micropore volume to SKC charcoal. S charcoal had the lowest surface area and micropore volume. J charcoal had the highest adsorption capacity at 101, 252 and 609 ppm of benzene. The gap in benzene adsorption capacity among the types of charcoal was the least at 609 ppm and the greatest at 101 ppm. J charcoal showed the highest adsorption capacity at 54, 106, 228 and 508 ppm of toluene. J charcoal and SKC charcoal had a similar adsorption capacity for acetone. J charcoal had the highest adsorption capacity for n-hexane. In the experiment featuring 10% breakthrough volume, 10% breakthrough occurred at 18 liters at 2065.9 ㎎/㎥ for J charcoal and at 20 liters at 1771.2 ㎎/㎥ for K charcoal. It was difficult to judge adsorption capacity by surface area and micropore volume of charcoal. J charcoal, which was similar to SKC charcoal in surface area and micropore volume, showed good adsorption capacity at common workplace concentrations. Conclusions: The adsorption capacity of J and K charcoal was superior compared with SKC charcoal. J and K charcoal can be considered appropriate for use as sampling media based on this result.

볼텍스쉐이커를 이용한 11개 나노물질의 분진날림 비교

이나루 ( Naroo Lee ),박진우 ( Jinwoo Park ) 한국산업보건학회 (구 한국산업위생학회) 2018 한국산업보건학회지 Vol.28 No.3

Objectives: Dustiness of nanomaterials is considered as exposure index of essential material. Research on dustiness of nanomaterial is needed to control exposure in workplaces. Method: Dustiness measurement using vortex shaker were installed in the laboratory. Nanomaterials, 1 g, was put in the glass test tube and shaked using vortex shaker. Aerosol dispersed was measured using scanning mobility particle sizer(SMPS) and optical particle counter(OPC). Mass concentration using PVC filter and cassette was measured and TEM grid sampling was conducted. Total particle concentration and size distribution were calculated. Image and chemical composition of particles in the air were observed using transmission electron microscopy and energy dispersive X-ray spectrometer. Eleven different test nanomaterials were used in the study. Results: Rank of mass concentration and particle number concentration were coincided in most cases. Rank of nanomateirals with low concentration were not coincided. Two types of fumed silica had the highest mass concentration and particle number concentration. Indium tin oxide, a mixture of indium oxide and tin oxide, had high mass concentration and particle number concentration. Indium oxide had very low mass concentration and particle number concentration. Agglomeration of nanoparticles in the air were observed in TEM analysis and size distribution. In this study, mass concentration and particle number concentration were coincided and two index can be used together. The range of dustiness in particle number concentration were too wide to measure in one method. Conclusion: Particle number concentration ranged from low concentration to high concentration depend on type of nanomaterial, and varied by preparation and amount of nanomaterial used. Further study is needed to measure dustiness of all nanomaterial as one reference method.

작업공정 및 활동에 따른 국내 작업장 납 노출특성 평가

이도희 ( Dohee Lee ),이나루 ( Naroo Lee ) 한국산업보건학회 2023 한국산업보건학회지 Vol.33 No.1

Objectives: The purpose of this study is to systematically identify situations where exposure levels are expected to be high by structuring domestic lead measurement data according to exposure processes and activities. Methods: Occupational exposure data on lead was collected from the results of the Evaluation of Reliability of Working Environment Measurement conducted by the government from 2019 to 2020. Lead exposure characteristics were analyzed by PROC (process category) and activity. The Risk Characterization Ratios (RCRs) of five PROCs according to ventilation type and lead content were evaluated using the MEASE (Metal's EASE) model. Results: The exposure data on lead (n=250) was classified into 12 PROCs and 12 activities, with an average concentration of 0.040 mg/㎥ and about 14% exceeding the occupational exposure limit of 0.05 mg/㎥. Processes with high exposure levels were PROC 7 (industrial spraying), 23 (open processing and transfer operations of molten metal), 24 (mechanical treatment), 25 (welding), and 26 (handling of powder containing lead). The results of evaluating RCR for the five PROCs were greater than 1 or close to 1 even if local exhaust ventilation was used. Conclusions: There is a possibility that the concentration of exposure is high in the casting and tapping of molten metal containing lead, mechanical treatment such as fracturing and abrasion, handling of powder, spraying, battery manufacturing, and waste battery recycling processes. It is necessary to implement chemical management policies for workplaces with such processes.

공기 중 탄소나노튜브 시료채취 시 사용하는 카세트 종류가 벽면 손실에 미치는 영향

함승헌,김송하,이진호,이나루,윤충식,Ham, Seunghon,Kim, Songha,Lee, Jinho,Lee, Naroo,Yoon, Chungsik 한국산업보건학회 2017 한국산업보건학회지 Vol.27 No.3

Objectives: The purposes of this study were to compare the surface resistance of cassettes according to the material, and to evaluate the wall deposition of carbon nanotubes(CNTs) by electrostatic loss in the inner wall of the cassette. Methods: Surface resistance was measured for three types of cassettes(25 mm polypropylene conductive cowl, 25 mm and 37 mm clear styrene cassettes) with a surface resistance meter. Also, electrostatic wall loss was measured at different weights of CNTs depending on the cassette. CNTs were laid on a weight dish with the cassette for five minutes to provide sufficient time to attach on the wall. Wipe sampling was performed to collect CNTs deposited on the wall and elemental carbon, known as a surrogate for CNTs, was analyzed. Results: The cassette with conductive materials(18% of black carbon) showed the lowest surface resistance($<1.21{\times}10^3{\Omega}$). Cassettes made from clear polystyrene showed the relatively highest surface resistance(25 mm: $10.02{\times}10^9{\Omega}$, 37 mm: $10.59{\times}10^9{\Omega}$). This means that particles are more likely to stick to the internal wall of styrene cassettes due to electrostatic electricity. This may lead to an underestimation of the airborne concentration of CNTs. The experiment showed that EC was not detected when using a 25 mm conductive cowl cassette, while EC was detected at the internal wall of 25 mm and 37 mm polystyrene cassettes. Conclusions: This study confirms that cassettes with a conductive cowl have low surface resistance and are more appropriate for CNT sampling. In addition, this finding could be applied for other types of particulate, especially regarding electrostatic charge and sampling.

원소탄소를 이용한 탄소나노튜브 및 탄소나노섬유 분석

김신아(Shina Kim),이나루(Naroo Lee) 환경독성보건학회 2016 한국독성학회 심포지움 및 학술발표회 Vol.2016 No.10

국내 디클로로메탄 제조·사용 사업장 근로자의 공정별 노출수준에 대한 작업환경측정값과 ECETOC TRA 모델값 비교연구

정수진 ( Sujin Jeong ),배계완 ( Gyewan Bae ),이나루 ( Naroo Lee ) 한국산업보건학회 2021 한국산업보건학회지 Vol.31 No.4

Objectives: By law, companies in Korea must periodically measure workers’ exposure to harmful chemicals (the system is called the Work Environment Monitoring Program (WMP)[a]) and report the results to the government. The government also measures exposure to monitor the WMP’s reliability (called Reliability Assessment (RA) for WMP[b]). The issue is that measured data from these two sources are so different that the objectivity of WMP needs to be confirmed by comparing the results using the European Centre for Ecotoxicology and Toxicology of Chemicals’ Targeted Risk Assessment (ECETOC TRA). Methods: Step 1: Data collection from WMP reports submitted by companies (n=586) and RA for WMP written by the government (n=33). Step 2: Data Standardization by key information included. Step 3: Data conversion to input-variables required to run the ECETOC TRA model, and run the model with specific data (n=514) which meet the predetermined exposure scenario. Step 4: Statistical data analysis by process category (PROC) and ventilation type from each source ([A] and [B]). Step 5: Additional analysis of any unexpected results. Results: The process categories of the production and handling of Dichloromethane were classified into 12 PROCs, and ten of them were selected to run ECETOC TRA. Modeled values tended to be higher than measured values from both sources. For the measured values from WMP, RCR distribution by PROC was narrow (0.197-0.267, 95% CI) and did not have a relationship with ventilation type, which differs from the tendency of the modeling result. Meanwhile, the measured values from RA for WMP were relatively widely distributed (0.301-1.177, 95% CI) by PROC. In particular PROCs (13,19) were high enough to exceed 1. Also, they become low with better ventilation types and appear differently depending on the ventilation type, similar to the model result. Conclusions: This study revealed that ECETOC TRA might have the potential to serve as a screening tool for exposure assessment and to be used as assistive method for WMP to estimate exposure. Further empirical study is required to confirm its availability as a screening tool.

노출기준 적용을 위한 세탁소용 석유계 솔벤트 특성규명

정지연,이광용,이나루,전홍진,김성진,이인섭,김광종 한국산업위생학회 2003 한국산업보건학회지 Vol.13 No.1

Although in the U.S perchloroethylene is the most commonly used in commercial dry cleaning shops, petroleum based dry cleaning solvent is the most frequently used in Korea. The solvent is a mixture of hydrocarbons, straight or branched chain aprraffins, naphthenes, and aromatic hydrocarbons. Exposure assessment at the cleaning shop was mainly focused on highly toxic substances, especially benzene, toluene, xylene, ethylbenzene, and 2-butoxyethanol in the solvents. However the contents of the toxic substances in the solvents are very small. Not only the exposure assessment for highly toxic substances is important, but also exposure for the petroleum based solvent itself is more important in dry cleaning shop. The specific aim of the present study was to identify the physical and the chemical properties of petroleum based dry cleaning solvents and to investigate the possivility of using occupational exposure standard of stoddard solvent for overall expostreassessment of petroleum based solvent. Four different petroleum based solvent(solvent A~solvent D). commonly used in Korda were analyzed and investigated for identifying the phtsical and chemical properties of those solvents. Molecula species of those solvents were C8~C12, and predominant molecular species were C10~C11 for solvent A, solvent C, solvent D. C9~C10 for solvent B. The proportion of paraffin, aromatic, naphthenic,and olefin compounds in dry cleaning solvents was 45.5~54.5%, 16.0~21.4%, 7.9%~15.8%, and 0.8%~1.0%, respectively. The range of boiling point, specific grabity, flash point found in material safety and data sheet made by the solvent manufacturing company was 150 ~210˚C. 0.76~0.79, and 30~44˚C., respectively. We conclude that petroleum based solvents used in dry cleaning shop is almost similar to stoddard solvent defined by ACGIH and NIOSH, and the occupational exposure standard of stoddrd solvent could be used in total exposure assessment of those solvents.

EDXRF에 의한 용접흄 중의 중금속의 비파괴 정량

박승현,정지연,유장진,이나루,유일재,송경석,이용학,한정희,김성진,박정선,정호근 한국산업위생학회 2001 한국산업보건학회지 Vol.11 No.3

The EDXRF(energy Dispersive X-ray Fluorescence Spec=trometer) technique was applied to the determination of heavy metals in welding fume. The EDXRF method designed in this study was a non-destructive analysis method. Samples were analyzed directly by EDXRF without any pre-treatment such as digestion and dilution. The samples used to evaluate such as digestion and dilution. the samples used to evaluate this method were laboratory samples exposed in a chamber connected with a welding fume generator. The samples were first analyzed using a non-destructive EDXRF method. The samples subsequently were analyzed using AAS method to verify accuracy of the EDXRF method. The purpose of this study was to evaluate the possibility of the non-destructive analysis of heavy metals in welding fume by EDXRF. The results of this study were as follow: 1. When the samples were collected under the open-face sampling condition, a surface distribution of welding fume particles on sample filters was uniform, which made non-destructive analysis possible. 2. The method was statistically evaluated according to the NIOSH(National Institute for Occupational Safety and Health) and HSE(Health and Safety Executive) Method. 3. The overall precision of the EDXRF method was calculated at 3.45% for Cr, 2.57% for Fe and 3.78% for Mn as relative standard deviation(RSD), respectively. The limits of detection were calculated at 0.46 ㎍/sample for Cr, 0.20 ㎍/sample for Fe and 1.14 ㎍/sample for Mn, respectively. 4. A comparison between the results of Cr, Fe, Mn analyzed by EDXRF and AAS was made in order to assess the accuracy of EDXRF method. The correlation coefficient between the results of EDXRF and AAS was 0.9985 for cr, 0,995 for Fe and 0.9982 for Mn, respectively. The overall uncertainty was determined to be ±12.31% , 8.64% and 11.91% for Cr, Fe and Mn, respectively. In conclusion, this study showed that Cr, Fe, Mn in welding fume were successfully analyzed by the EDXRF without any sample pre-treatment such as digestion and dilution and a good correlation between the results of EDXRF and AAS was obtained. It was thus possible to use the EDXRF technique as an analysis method of working environment samples. The EDXRF method was an efficient method in a non-destructive analysis of heavy metals in welding fume.

자동차 프레스 공정에 있어서 직무 및 누적소음기 설정치 차이에 따른 작업자의 소음노출 평가

정지연,박승현,이광용,이나루,유기호,박정선,정호근 한국산업위생학회 2001 한국산업보건학회지 Vol.11 No.3

Noise-induced hearing loss(NIHL) was the highest rate(43.5%∼58.5% from 1996 to 1998) of positive findings through specific medical program in Korea. There were much more NIHL at workers of automobile manufacturing factories than other manufacturing factories. The specific aim of the present study was to determine the noise exposure of automobile press lines, according to their job titles, press line types(auto, semiauto), dosimeter parameters setting. There were a total 11 press lines sampled at a automobile manufacturing company. Among those press lines, 10 press lines were autolines with acoustic enclosure, one semiauto press line was no aucostic enclosure Noise exposure data were sampled for an work shift using noise dosimeter, which recorded both time-weighted average(TWA) and 1-min average. The mean OSHA TWA(Korea TWA with threshold 90) was 80.7 ㏈(A) ±4.7 ㏈(A) for leader, 82.8 ㏈(A) ±4.5 ㏈(A) for pallette man. 76.7 ㏈(A) ±4.3 ㏈(A) for press operators, 76.6 ㏈(A) ±5.6 ㏈(A) for crane operators, 77.1 ㏈(A) ±2.8 ㏈(A) for forklift drivers, whereas the mean NIOSH TWA was 88.9 ㏈(A) ± 1.7㏈(A) for leader, 89.6 ㏈(A) ±21.㏈(A) for pallette man, 86.7㏈(A) ±1.8㏈(A) for press operators, 88.5 ㏈(A) ±2.0 ㏈(A) for crane operators, 87.7 ㏈(A) ±1.0 ㏈(A) for forklift drivers. While L10 for NIOSH TWA samples was 84.8 ㏈(A) ∼ 87.3 ㏈(A), L10 for OSHA TWA samples was 69.5 ㏈(A) ∼ 77.4 ㏈(A). L10 means that the TWA for 90% of the samples exceeded L10. Among OSHA TWA(Korea TWA with threshold 90) samples for pallette man, 7.7 % exceeded 90 ㏈(A), the OSHA permissible exposure level, but OSHA TWA samples for the other job titles didn't. Among NIOSH TWA samples, the samples over 85 ㏈(A), the NIOSH recommended exposure limit, was 100%(leaders), 83.3 %(operators), 97.4%(pallette man), 100%(forklift drivers), 91.7 %(crane operator). The results of One-way random effects analysis of variance models shows that the difference between job titles was significant by OSHA TWA(p<0.05), but not significant by NIOSH TWA(p>0.05). NIOSH TWA samples were significantly higher than OSHA TWA samples(P<0.05). Regression analysis was used to obtain relationships between OSHA TWA samples and NIOSH TWA samples. In this case the coefficient of determination = 0.09, which shows the high degree association between two methods. Regression equation, NIOSH TWA = 0.552 * OSHA TWA + 42.13 ㏈(A), shows that if OSHA TWA is known, NIOSH TWA can be predicted by the equation. The mean TWA difference between threshold 80dBA and 90dBA was significant(p<0.01). While the TWA noise exposures were 7.7% above the Korea(OSHA) PEL, they were more than 83.3% over NIOSH REL. Automobile workers were exposed to noise level that could be potentially damaging to their hearing. It found that their approximately 25% excess risk of hearing loss even if a worker is protected to the PEL in according to NIOSH study. So these data demonstrate the need of engineering control for noise reduction of press line and comprehensive hearing conservation programs for whole workers(press operator, crane operator, forklift driver). The Noise measurement criteria of Korea has no definition about threshold value. So I suggest that we should set the threshold set the threshold value by law.