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Chung Sik Yoon
Department of Occupational Health, Graduate School of Public Health, Seoul National University, Seoul, Republic of Korea

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Research article
Published: 14 September 2020 in PLOS ONE
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Enclosed underground excavation worksite has an environment with poor ventilation and exposure to hazardous substances from diesel engine exhaust and construction materials. The objective of this study was to evaluate the exposure level of elemental carbon (EC), organic carbon (OC), total carbon (TC), polycyclic aromatic hydrocarbons (PAHs), dust and crystalline silica (CS) during underground excavation work for top down construction buildings. Active local air sampling for EC, OC, and TC (n = 105), PAHs (n = 50), dust (n = 34) and CS (n = 34) was conducted from inside and outside the excavator at underground excavation workshop in four different construction sites. EC, OC, TC and CS were sampled with each respirable and total particulates. EC, OC, and TC were collected on quartz-filter and analyzed using the thermal optical transmittance method. PAHs was collected on polytetrafluorethylene filter with XAD-2 and analyzed using liquid chromatography with fluorescence detector. CS and particulates were collected on poly vinyl chloride filter and analyzed using fourier-transform infrared spectroscopy. The geometric mean of respirable EC, OC, TC, total PAHs, respirable dust and respirable CS were 8.69 μg/m3, 34.32 μg/m3, 44.96 μg/m3, 6.818 μg/m3 0.13 mg/m3 and 0.02 mg/m3 from inside the excavator and 33.20 μg/m3, 46.53 μg/m3, 78.21 μg/m3, 3.934 μg/m3, 0.9 mg/m3 and 0.08 mg/m3 from outside the excavator (underground excavation workshop), respectively. The EC and RCS concentration from outside the excavator is significantly higher than that of inside the excavator (p<0.01). The worksite with rock ground, higher vehicle density, blasting and enclosed environments had higher exposure to EC than other sites (p<0.05). There was no significant difference of EC concentration between total and respirable particulates. In top down construction sites, EC concentrations during underground excavation work exceeded recommended exposure limits as 20 μg/m3, accounted for about 50% of the total sample, and the level of concentration of RCS exceeded 1.5 times of occupational exposure limit, 0.05 mg/m3. Efforts are needed to minimize exposure to diesel engine exhaust and silica in underground excavation sites. Management of diesel engine vehicle, supply of fresh air and ventilation and introducing water facilities to create wet environment in underground worksites are strongly suggested.

ACS Style

Hyunhee Park; Eunsong Hwang; Miyeon Jang; ChungSik Yoon. Exposure assessment of elemental carbon, polycyclic aromatic hydrocarbons and crystalline silica at the underground excavation sites for top-down construction buildings. PLOS ONE 2020, 15, e0239010 .

AMA Style

Hyunhee Park, Eunsong Hwang, Miyeon Jang, ChungSik Yoon. Exposure assessment of elemental carbon, polycyclic aromatic hydrocarbons and crystalline silica at the underground excavation sites for top-down construction buildings. PLOS ONE. 2020; 15 (9):e0239010.

Chicago/Turabian Style

Hyunhee Park; Eunsong Hwang; Miyeon Jang; ChungSik Yoon. 2020. "Exposure assessment of elemental carbon, polycyclic aromatic hydrocarbons and crystalline silica at the underground excavation sites for top-down construction buildings." PLOS ONE 15, no. 9: e0239010.

Original article
Published: 02 September 2020 in Indoor Air
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Harmful emissions including particulates, volatile organic compounds, and aldehydes are generated during three‐dimensional (3D) printing. Ultrafine particles are particularly important due to their ability to penetrate deep into the lung. We modeled inhalation exposure by particle size during 3D printing. A total of six thermoplastic filaments were used for printing under manufacturer’s recommended conditions, and particle emissions in the size range between 10 nm and 10 μm were measured. The inhalation exposure dose including inhaled and deposited doses was estimated using a mathematical model. For all materials, the number of particles between 10 nm and 1 μm accounted for a large proportion among the released particles, withnano‐sized particles being the dominant size. More than 1.3×109nano‐sized particles/kgbw/g (95.3±104.0 ng/kgbw/g) could be inhaled, and a considerable amount were deposited in respiratory regions. The total deposited dose in terms of particle number was 3.1×108 particles/kgbw/g (63.6% of the total inhaled dose), and most (41.3%) were deposited in the alveolar region. The total mass of particles deposited was 19.8±16.6 ng/kgbw/g, with 10.1% of the total mass deposited in the alveolar region. Given our findings, the inhalation exposure levelis mainly determined by printing conditions, particularly, the filament type and manufacturer‐recommended extruder temperature.

ACS Style

Jihoon Park; Oh‐Hun Kwon; ChungSik Yoon; Mijin Park. Estimates of particulate matter inhalation doses during three‐dimensional printing. Indoor Air 2020, 31, 392 -404.

AMA Style

Jihoon Park, Oh‐Hun Kwon, ChungSik Yoon, Mijin Park. Estimates of particulate matter inhalation doses during three‐dimensional printing. Indoor Air. 2020; 31 (2):392-404.

Chicago/Turabian Style

Jihoon Park; Oh‐Hun Kwon; ChungSik Yoon; Mijin Park. 2020. "Estimates of particulate matter inhalation doses during three‐dimensional printing." Indoor Air 31, no. 2: 392-404.

Original article
Published: 23 March 2020 in Indoor Air
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Physicochemical properties between colloidal engineered nanomaterials (ENM) and aerosols released from consumer spray products were characterized. A dynamic light scattering (DLS), transmission electron microscopy (TEM) and inductively coupled plasma‐mass spectrometer (ICP‐MS) were used to evaluate the suspended ENMs in the products. Direct‐reading instruments, TEM and ICP‐MS were used to characterize the properties of aerosolized ENMs. The aerosolized organic compounds with ENMs were assumed to be vaporized for a short time after spraying. The median diameter of ENMs in product solutions measured by DLS were about 200‐350 nm, while individual particle were confirmed from 3 to 50 nm by TEM. The size of aerosolized ENMs was ranged 7‐44 nm and their aggregates were about 100‐1000 nm in near distance. Some inorganic substances including raw nanomaterials were also found in the aerosol. The particles released from the propellant sprays were identified in far distance, while they were not found in far distance when pump sprays were used. The number concentration from the propellant sprays increased up to 6000 particles/cm3/g at near distance and dispersed to far distance, while the most of droplets emitted from pump sprays were settled down near sprayer's location. We found other metals besides labeled ENMs are included in each product and the characteristics of the particles are different when they are sprayed.

ACS Style

Jihoon Park; Seunghon Ham; SunJu Kim; Miyeon Jang; Jinho Lee; Sungkyoon Kim; Donguk Park; Kiyoung Lee; Hyunmi Kim; Pilje Kim; ChungSik Yoon. Physicochemical characteristics of colloidal nanomaterial suspensions and aerosolized particulates from nano‐enabled consumer spray products. Indoor Air 2020, 30, 925 -941.

AMA Style

Jihoon Park, Seunghon Ham, SunJu Kim, Miyeon Jang, Jinho Lee, Sungkyoon Kim, Donguk Park, Kiyoung Lee, Hyunmi Kim, Pilje Kim, ChungSik Yoon. Physicochemical characteristics of colloidal nanomaterial suspensions and aerosolized particulates from nano‐enabled consumer spray products. Indoor Air. 2020; 30 (5):925-941.

Chicago/Turabian Style

Jihoon Park; Seunghon Ham; SunJu Kim; Miyeon Jang; Jinho Lee; Sungkyoon Kim; Donguk Park; Kiyoung Lee; Hyunmi Kim; Pilje Kim; ChungSik Yoon. 2020. "Physicochemical characteristics of colloidal nanomaterial suspensions and aerosolized particulates from nano‐enabled consumer spray products." Indoor Air 30, no. 5: 925-941.

Journal article
Published: 31 December 2019 in Safety and Health at Work
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Ammonia and hydrogen sulfide are harmful gases generated during aerobic/anaerobic bacterial decomposition of livestock manure. We evaluated ammonia and hydrogen sulfide concentrations generated from workplaces at livestock farms and to determine environmental factors influencing the gas concentrations. Five commercial swine farms and five poultry farms were selected for monitoring. Real-time monitors were used to measure the ammonia and hydrogen sulfide concentrations and environmental conditions during the manure-handling processes. Monitoring was conducted in the manure storage facility, and composting facility. Information on the farm conditions was also collected through interview and walkthrough survey. The ammonia concentrations were significantly higher at the swine composting facilities(9.5 to 43.2 ppm) than other manure handling facilities at the swine and poultry farms, and high concentrations of hydrogen sulfide were identified during the manure agitation and mixing process at the swine manure storage facilities(6.9 to 19.5 ppm). At the poultry manure-handling facilities, the ammonia concentration was higher during the manure-handling processes(2.6 to 57.9 ppm) and very low hydrogen sulfide concentrations(0 to 3.4 ppm) were detected. The air temperature and relative humidity, volume of the facility, duration of manure storage, and the number of animals influenced the gas concentrations. High level of hazardous gases was generated during manure handling and some cases showed risky level to workers’ health and safety. Some of farm operational factors were also identified to influence the gas levels. By controlling and improving these factors, it would be possible to protect workers’ safety and health from occupational risks.

ACS Style

Jihoon Park; Taesun Kang; Yong Heo; Kiyoung Lee; Kyungran Kim; Kyungsuk Lee; ChungSik Yoon. Evaluation of Short-Term Exposure Levels on Ammonia and Hydrogen Sulfide During Manure-Handling Processes at Livestock Farms. Safety and Health at Work 2019, 11, 109 -117.

AMA Style

Jihoon Park, Taesun Kang, Yong Heo, Kiyoung Lee, Kyungran Kim, Kyungsuk Lee, ChungSik Yoon. Evaluation of Short-Term Exposure Levels on Ammonia and Hydrogen Sulfide During Manure-Handling Processes at Livestock Farms. Safety and Health at Work. 2019; 11 (1):109-117.

Chicago/Turabian Style

Jihoon Park; Taesun Kang; Yong Heo; Kiyoung Lee; Kyungran Kim; Kyungsuk Lee; ChungSik Yoon. 2019. "Evaluation of Short-Term Exposure Levels on Ammonia and Hydrogen Sulfide During Manure-Handling Processes at Livestock Farms." Safety and Health at Work 11, no. 1: 109-117.

Journal article
Published: 23 December 2019 in Environmental Research
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Polyhexamethyleneguanidine (PHMG) is widely used as a disinfectant to prevent microbial contamination in ultrasonic humidifiers in Korea; however, sales have been prohibited by the government after an outbreak of severe lung injury among humidifier disinfectant users. This study was therefore conducted to determine the characteristics of PHMG particles in aqueous solution and to investigate the behavior of airborne particles generated when using PHMG as a humidifier disinfectant. Three types of PHMG were selected (manufactured in Korea, USA, and China), with dynamic light scattering (DLS) used to determine their behavioral characteristics in aqueous solution. To determine the airborne behavioral characteristics, PHMG was diluted to obtain high (62.5–65 ppm) and low (6.25–6.5 ppm) concentrations, and then real-time monitoring instruments were used to measure the effect of using a diffusion dryer and thermodenuder to control moisture in a cleanroom. A polycarbonate filter sample was analyzed by field emission-scanning electron microscope-energy dispersive spectrometry (FE-SEM-EDS) to determine the particle morphology. The DLS intensity results for the three products showed a slightly right-shifted (~100 nm) bimodal distribution relative to the airborne particle size distribution. The size of the airborne PHMG particles increased during the spraying due to aggregation, with the particle size of aggregated particles confirmed by FE-SEM to be approximately 20 nm or more. As the PHMG concentration increased by 10 times, the airborne concentrations measured by the real-time monitoring instrument increased by 2–3 times for nanoparticles, and by 45–85 times for 1–10 μm particles during humidifier operation; however, 99% of the particles generated could be classified as PM1. Without ventilation, even after operating the humidifier, the PHMG particles could be airborne for about 2 h until the background concentration was reached. Therefore, we found that the airborne behavior was affected by PHMG concentration. Products from different manufacturers had no effect on the airborne behavior.

ACS Style

SunJu Kim; SeonKyeong Park; Hyeri Jo; Seungwhan Song; Seunghon Ham; ChungSik Yoon. Behavioral characteristics of polyhexamethyleneguanidine (PHMG) particles in aqueous solution and air when sprayed into an ultrasonic humidifier. Environmental Research 2019, 182, 109078 .

AMA Style

SunJu Kim, SeonKyeong Park, Hyeri Jo, Seungwhan Song, Seunghon Ham, ChungSik Yoon. Behavioral characteristics of polyhexamethyleneguanidine (PHMG) particles in aqueous solution and air when sprayed into an ultrasonic humidifier. Environmental Research. 2019; 182 ():109078.

Chicago/Turabian Style

SunJu Kim; SeonKyeong Park; Hyeri Jo; Seungwhan Song; Seunghon Ham; ChungSik Yoon. 2019. "Behavioral characteristics of polyhexamethyleneguanidine (PHMG) particles in aqueous solution and air when sprayed into an ultrasonic humidifier." Environmental Research 182, no. : 109078.

Cover image
Published: 06 December 2019 in Indoor Air
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ACS Style

Haejoon Jeon; Jihoon Park; SunJu Kim; Kyungho Park; ChungSik Yoon. Cover Image. Indoor Air 2019, 30, 1 .

AMA Style

Haejoon Jeon, Jihoon Park, SunJu Kim, Kyungho Park, ChungSik Yoon. Cover Image. Indoor Air. 2019; 30 (2):1.

Chicago/Turabian Style

Haejoon Jeon; Jihoon Park; SunJu Kim; Kyungho Park; ChungSik Yoon. 2019. "Cover Image." Indoor Air 30, no. 2: 1.

Original article
Published: 19 November 2019 in Indoor Air
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Ultrafine particles and other hazardous materials are emitted during 3D printing, but the effect of temperature on such particles has not been studied systematically. The aim of this study was to evaluate the effect of temperature on the emission rate of particulate matter during fused deposition modeling (FDM) three‐dimensional (3D) printing using different filament types. The number concentration of particles was measured with direct‐reading instruments in an exposure chamber at various temperatures while using four filament materials during 3D printing. The temperature was increased from 185 to 290°C in 15°C increments, while incorporating the manufacturer‐recommended operating conditions. The emission rate increased gradually as the temperature increased for all filament types, and temperature was the key factor affecting the emission rate after filament type. For all filaments, at the lowest operating temperature, the emission rate was 107‐109 particles/min, whereas the emission rate at the highest temperature was about 1011 particles/min, i.e., 100‐10,000 times higher than the emission rate at the lowest temperature. To reduce particle emissions from 3D printing, we recommend printing at the lowest temperature possible or using low‐emission materials.

ACS Style

Haejoon Jeon; Jihoon Park; SunJu Kim; Kyungho Park; ChungSik Yoon. Effect of nozzle temperature on the emission rate of ultrafine particles during 3D printing. Indoor Air 2019, 30, 306 -314.

AMA Style

Haejoon Jeon, Jihoon Park, SunJu Kim, Kyungho Park, ChungSik Yoon. Effect of nozzle temperature on the emission rate of ultrafine particles during 3D printing. Indoor Air. 2019; 30 (2):306-314.

Chicago/Turabian Style

Haejoon Jeon; Jihoon Park; SunJu Kim; Kyungho Park; ChungSik Yoon. 2019. "Effect of nozzle temperature on the emission rate of ultrafine particles during 3D printing." Indoor Air 30, no. 2: 306-314.

Journal article
Published: 15 November 2019 in Sustainability
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This study aimed to compare sample pretreatment procedures for the identification and quantification of asbestos. The performance of visual estimation and point counting procedures for evaluating asbestos-containing waste was investigated, and the effect of analytical experience was studied. The efficacy of pretreatments for the identification and quantification of asbestos in various sample matrices was compared. To evaluate the effect of experience on analytical accuracy, three analysts with different analytical experiences were selected. There were significant differences in the quantitative analysis results obtained using different pretreatments. False negatives were reported when asbestos, especially amphiboles, were analyzed by a less-experienced analyst. Quantification via point counting and visual estimation resulted in differences in the asbestos content. The results of point counting were more accurate than those of visual estimation for all analysts, regardless of the asbestos type and concentration. Experience in asbestos analysis affected accuracy and precision. The findings show that pretreatment is an important factor in qualitative analysis. Appropriate pretreatments should be assigned based on the properties of the sample. For quantitative analysis, the accuracy of the results depends on the experience of the analyst. Until analysts are fully trained, all their analysis results should be checked by an experienced analyst. Point counting is an adequate quantitative method for analyzing samples with low concentrations.

ACS Style

Seunghon Ham; Sungho Hwang; ChungSik Yoon. Comparison of Methods for Pretreatment and Quantification of Bulk Asbestos Samples for Polarized Light Microscopy Analysis to Evaluate Asbestos-Containing Waste. Sustainability 2019, 11, 6440 .

AMA Style

Seunghon Ham, Sungho Hwang, ChungSik Yoon. Comparison of Methods for Pretreatment and Quantification of Bulk Asbestos Samples for Polarized Light Microscopy Analysis to Evaluate Asbestos-Containing Waste. Sustainability. 2019; 11 (22):6440.

Chicago/Turabian Style

Seunghon Ham; Sungho Hwang; ChungSik Yoon. 2019. "Comparison of Methods for Pretreatment and Quantification of Bulk Asbestos Samples for Polarized Light Microscopy Analysis to Evaluate Asbestos-Containing Waste." Sustainability 11, no. 22: 6440.

Journal article
Published: 18 August 2018 in Safety and Health at Work
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The photolithography process in the semiconductor industry uses various chemicals with little information on their constitution. This study aimed to identify the chemical constituents of photoresist (PR) products and their by-products and to compare these constituents with material safety data sheets (MSDSs) and analytical results. A total of 51 PRs with 48 MSDSs were collected. Analysis consisted of two parts: First, the constituents of the chemical products were identified and analyzed using MSDS data; second, for verification of the by-products of PR, volatile organic compounds were analyzed. The chemical constituents were categorized according to hazards. Forty-five of 48 products contained trade secrets in amounts ranging from 1 to 65%. A total of 238 ingredients with multiple counting (35 ingredients without multiple counting) were identified in the MSDS data, and 48.7% of ingredients were labeled as trade secrets under the Korea Occupational Safety and Health Act. The concordance rate between the MSDS data and the analytical result was 41.7%. The by-product analysis identified 129 chemicals classified according to Chemical Abstracts Service No., with 17 chemicals that are carcinogenic, mutagenic, and reprotoxic substances. Formaldehyde was found to be released from 12 of 21 products that use novolak resin. We confirmed that several PRs contain carcinogens, and some were not specified in the toxicological information in the MSDS. Hazardous chemicals, including benzene and formaldehyde, are released from PRs products as by-products. Therefore, it is necessary to establish a systematic management system for chemical compounds and the working environment.

ACS Style

Miyeon Jang; ChungSik Yoon; Jihoon Park; Ohhun Kwon. Evaluation of Hazardous Chemicals with Material Safety Data Sheet and By-products of a Photoresist Used in the Semiconductor-Manufacturing Industry. Safety and Health at Work 2018, 10, 114 -121.

AMA Style

Miyeon Jang, ChungSik Yoon, Jihoon Park, Ohhun Kwon. Evaluation of Hazardous Chemicals with Material Safety Data Sheet and By-products of a Photoresist Used in the Semiconductor-Manufacturing Industry. Safety and Health at Work. 2018; 10 (1):114-121.

Chicago/Turabian Style

Miyeon Jang; ChungSik Yoon; Jihoon Park; Ohhun Kwon. 2018. "Evaluation of Hazardous Chemicals with Material Safety Data Sheet and By-products of a Photoresist Used in the Semiconductor-Manufacturing Industry." Safety and Health at Work 10, no. 1: 114-121.

Brief report
Published: 05 June 2018 in International Journal of Environmental Research and Public Health
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Background: Hospital-acquired pneumonia (HAP) is an inflammatory condition of the lung that develops at least 48–72 h after admission. HAP is contracted by both intensive care unit (ICU) and non-ICU patients, but no studies have examined the risk of HAP in patients admitted to the emergency department (ED). This study investigated the risk of developing HAP in ED patients and compared the occurrence of HAP 3–10 days after the first day of hospitalization in patients hospitalized via ED with those hospitalized via outpatient clinics. Methods: We analyzed the 2010 National Inpatient Sample data collected by the Health Insurance Review and Assessment Service in South Korea. After propensity score matching for age, sex, residential area, hospital, and diseases, 153,130 inpatients (76,565 admitted via ED and 76,565 admitted via outpatient clinics) were included in the analysis. The diagnosis of pneumonia was based on the International Classification of Diseases and Related Health Problems 10th Revision (Pneumonia, all (J12–J18); Pneumonia, bacterial (J13–J15); Pneumonia, non-bacterial (J12, J16, J17); and Pneumonia, unspecified (J18)). Results: The percentage of newly diagnosed cases of pneumonia in inpatients admitted via ED was significantly higher than that in inpatients admitted via outpatient clinics. After propensity score matching for baseline characteristics, the likelihood of developing pneumonia (excluding the category of ‘Pneumonia, non-bacterial’) in inpatients hospitalized via ED was significantly increased by 1.33–1.97-fold. The cumulative incidence of pneumonia was also significantly higher in patients admitted via ED than in those hospitalized via outpatient clinics. Conclusions: ED visits may be an important risk factor for the development of HAP.

ACS Style

Jin-Young Min; Hye-Jin Kim; ChungSik Yoon; Kiyoung Lee; Myoungsouk Yeo; Kyoung-Bok Min. Hospital-Acquired Pneumonia among Inpatients via the Emergency Department: A Propensity-Score Matched Analysis. International Journal of Environmental Research and Public Health 2018, 15, 1178 .

AMA Style

Jin-Young Min, Hye-Jin Kim, ChungSik Yoon, Kiyoung Lee, Myoungsouk Yeo, Kyoung-Bok Min. Hospital-Acquired Pneumonia among Inpatients via the Emergency Department: A Propensity-Score Matched Analysis. International Journal of Environmental Research and Public Health. 2018; 15 (6):1178.

Chicago/Turabian Style

Jin-Young Min; Hye-Jin Kim; ChungSik Yoon; Kiyoung Lee; Myoungsouk Yeo; Kyoung-Bok Min. 2018. "Hospital-Acquired Pneumonia among Inpatients via the Emergency Department: A Propensity-Score Matched Analysis." International Journal of Environmental Research and Public Health 15, no. 6: 1178.

Journal article
Published: 03 June 2018 in International Journal of Environmental Research and Public Health
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The goal of this study was to evaluate the hazardous chemical exposure control system in a semiconductor manufacturing company and recommend an appropriate exposure surveillance system for hazardous agents. We reviewed compliance-based chemical exposure data compiled between 2012 and 2014 by the study company. The chemical management system, characteristics of chemical use and hazardous gas monitoring system were also investigated. We evaluated the airborne isopropyl alcohol (IPA) and acetone generally used as cleaning solvents, volatile organic compounds and metals levels using internationally recommended sampling and analytical methods. Based on the results of past working environment measurement data and of our investigation, the overall current exposure to chemicals by semiconductor workers during routine production work appears to be controlled below occupational exposure limits. About 40% of chemical products used were found to contain at least one unidentifiable trade-secret substance. There are several situations and maintenance tasks that need special attention to reduce exposure to carcinogens as much as possible. In addition, a job-exposure matrix as a tool of surveillance system that can examine the exposure and health status of semiconductor workers according to type of operation and type of job or task is recommended.

ACS Style

Sangjun Choi; ChungSik Yoon; Seungwon Kim; Won Kim; Kwonchul Ha; Jeeyeon Jeong; Jongcheul Kim; Jungah Shin; Donguk Park. Comprehensive Evaluation of Hazardous Chemical Exposure Control System at a Semiconductor Manufacturing Company in South Korea. International Journal of Environmental Research and Public Health 2018, 15, 1162 .

AMA Style

Sangjun Choi, ChungSik Yoon, Seungwon Kim, Won Kim, Kwonchul Ha, Jeeyeon Jeong, Jongcheul Kim, Jungah Shin, Donguk Park. Comprehensive Evaluation of Hazardous Chemical Exposure Control System at a Semiconductor Manufacturing Company in South Korea. International Journal of Environmental Research and Public Health. 2018; 15 (6):1162.

Chicago/Turabian Style

Sangjun Choi; ChungSik Yoon; Seungwon Kim; Won Kim; Kwonchul Ha; Jeeyeon Jeong; Jongcheul Kim; Jungah Shin; Donguk Park. 2018. "Comprehensive Evaluation of Hazardous Chemical Exposure Control System at a Semiconductor Manufacturing Company in South Korea." International Journal of Environmental Research and Public Health 15, no. 6: 1162.

Original articles
Published: 07 May 2018 in Human and Ecological Risk Assessment: An International Journal
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(1→3)-β-D-glucan causes respiratory airway irritation as a biomarker for biological agents in indoor environments. We evaluated (1→3)-β-D-glucan levels in three microbiology laboratories every month for one year by applying a health risk assessment methodology and determined the associated environmental factors. In total, 192 samples were retrieved using a new, two-stage bioaerosol cyclone (BC 221) sampler. Analysis of (1→3)-β-D-glucan was performed using the kinetic Limulus amebocyte lysate assay. This study revealed that illumination was negatively correlated with (1→3)-β-D-glucan (r = −0.206, p = 0.04) and that relative humidity and season were positively associated with (1→3)-β-D-glucan (p < 0.05). Among the environmental factors, season (particularly spring) was most significantly associated with (1→3)-β-D-glucan levels. Future studies regarding the relationship between (1→3)-β-D-glucan levels and other biological agents, including fungi, bacteria, endotoxin, and other environmental factors, should be assessed. The hazard quotient in summer is higher than the acceptable level of 1 for children if they stay in laboratories for 12 hours. Inhalation exposure to (1→3)-β-D-glucan by children in microbiology laboratories is thus not safe in summer.

ACS Style

Sungho Hwang; Dong Uk Park; ChungSik Yoon. Seasonal variation in (1→3)-β-D-glucan levels with health risk assessment and related factors in indoor environments of microbiology laboratories. Human and Ecological Risk Assessment: An International Journal 2018, 25, 1096 -1106.

AMA Style

Sungho Hwang, Dong Uk Park, ChungSik Yoon. Seasonal variation in (1→3)-β-D-glucan levels with health risk assessment and related factors in indoor environments of microbiology laboratories. Human and Ecological Risk Assessment: An International Journal. 2018; 25 (5):1096-1106.

Chicago/Turabian Style

Sungho Hwang; Dong Uk Park; ChungSik Yoon. 2018. "Seasonal variation in (1→3)-β-D-glucan levels with health risk assessment and related factors in indoor environments of microbiology laboratories." Human and Ecological Risk Assessment: An International Journal 25, no. 5: 1096-1106.

Journal article
Published: 31 March 2018 in International Journal of Environmental Research and Public Health
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We assessed the exposure of semiconductor workers to extremely low frequency-magnetic fields (ELF-MF) and identified job characteristics affecting ELF-MF exposure. These were demonstrated by assessing the exposure of 117 workers involved in wafer fabrication (fab) and chip packaging wearing personal dosimeters for a full shift. A portable device was used to monitor ELF-MF in high temporal resolution. All measurements were categorized by operation, job and working activity during working time. ELF-MF exposure of workers were classified based on the quartiles of ELF-MF distribution. The average levels of ELF-MF exposure were 0.56 µT for fab workers, 0.59 µT for chip packaging workers and 0.89 µT for electrical engineers, respectively. Exposure to ELF-MF differed among types of factory, operation, job and activity. Workers engaged in the diffusion and chip testing activities showed the highest ELF-MF exposure. The ELF-MF exposures of process operators were found to be higher than those of maintenance engineers, although peak exposure and/or patterns varied. The groups with the highest quartile ELF-MF exposure level are operators in diffusion, ion implantation, module and testing operations, and maintenance engineers in diffusion, module and testing operations. In conclusion, ELF-MF exposure among workers can be substantially affected by the type of operation and job, and the activity or location.

ACS Style

Sangjun Choi; Wonseok Cha; Jihoon Park; Seungwon Kim; Won Kim; ChungSik Yoon; Ju-Hyun Park; Kwonchul Ha; Donguk Park. Extremely Low Frequency-Magnetic Field (ELF-MF) Exposure Characteristics among Semiconductor Workers. International Journal of Environmental Research and Public Health 2018, 15, 642 .

AMA Style

Sangjun Choi, Wonseok Cha, Jihoon Park, Seungwon Kim, Won Kim, ChungSik Yoon, Ju-Hyun Park, Kwonchul Ha, Donguk Park. Extremely Low Frequency-Magnetic Field (ELF-MF) Exposure Characteristics among Semiconductor Workers. International Journal of Environmental Research and Public Health. 2018; 15 (4):642.

Chicago/Turabian Style

Sangjun Choi; Wonseok Cha; Jihoon Park; Seungwon Kim; Won Kim; ChungSik Yoon; Ju-Hyun Park; Kwonchul Ha; Donguk Park. 2018. "Extremely Low Frequency-Magnetic Field (ELF-MF) Exposure Characteristics among Semiconductor Workers." International Journal of Environmental Research and Public Health 15, no. 4: 642.

Research article
Published: 30 August 2017 in Environmental Science & Technology
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This study aimed to evaluate particle emission characteristics and to evaluate several control methods used to reduce particle emissions during three-dimensional (3D) printing. Experiments for particle characterization were conducted to measure particle number concentrations, emission rates, morphology, and chemical compositions under manufacturer-recommended and consistent-temperature conditions with seven different thermoplastic materials in an exposure chamber. Eight different combinations of the different control methods were tested, including an enclosure, an extruder suction fan, an enclosure ventilation fan, and several types of filter media. We classified the thermoplastic materials as high emitter (>1011 #/min), medium emitters (109 #/min −1011 #/min), and low emitters (<109 #/min) based on nanoparticle emissions. The nanoparticle emission rate was at least 1 order of magnitude higher for all seven filaments at the higher consistent extruder temperature than at the lower manufacturer-recommended temperature. Among the eight control methods tested, the enclosure with a high-efficiency particulate air (HEPA) filter had the highest removal effectiveness (99.95%) of nanoparticles. Our recommendations for reducing particle emissions include applying a low temperature, using low-emitting materials, and instituting control measures like using an enclosure around the printer in conjunction with an appropriate filter (e.g., HEPA filter) during 3D printing.

ACS Style

Ohhun Kwon; ChungSik Yoon; Seunghon Ham; Jihoon Park; Jinho Lee; Danbi Yoo; Yoojin Kim. Characterization and Control of Nanoparticle Emission during 3D Printing. Environmental Science & Technology 2017, 51, 10357 -10368.

AMA Style

Ohhun Kwon, ChungSik Yoon, Seunghon Ham, Jihoon Park, Jinho Lee, Danbi Yoo, Yoojin Kim. Characterization and Control of Nanoparticle Emission during 3D Printing. Environmental Science & Technology. 2017; 51 (18):10357-10368.

Chicago/Turabian Style

Ohhun Kwon; ChungSik Yoon; Seunghon Ham; Jihoon Park; Jinho Lee; Danbi Yoo; Yoojin Kim. 2017. "Characterization and Control of Nanoparticle Emission during 3D Printing." Environmental Science & Technology 51, no. 18: 10357-10368.

Research article
Published: 24 May 2017 in Environmental Science & Technology
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We evaluated the spatial-temporal dispersion of airborne nanomaterials during the use of spray consumer products and estimated the level of consumer inhalation exposure. A total of eight spray products including five propellant and three pump types were selected to evaluate the dispersion of airborne nanoparticles across time and space in a cleanroom which could control the background particles. Four products were advertised to contain silver and one contained titanium nanoparticles, while three products were specified no ENM but as being manufactured through the use of nanotechnology. We used direct-reading instruments with a thermodesorber unit to measure the particles (number, mass, surface area), as well as filter sampling to examine physicochemical characteristics. Sampling was conducted simultaneously at each location (1 m, near-field; 2, 3 m, far-field) by distance from the source. We estimated the inhaled doses at the breathing zone, and the doses deposited in each part of the respiratory tract using the experimental data and mathematical models. Nanoparticles released from the propellant sprays persisted in the air and dispersed over a large distance due to their small size (1466–5565 particles/cm3). Conversely, the pump sprays produced larger droplets that settled out of the air relatively close to the source, so the concentration was similar to background level (<200 particles/cm3). The estimates of inhalation exposure also suggested that exposure to nanoparticles was greater with propellant sprays (1.2 × 108 ± 4.0 × 107 particles/kgbw/day) than pump sprays (2.7 × 107 ± 6.5 × 106 particles/kgbw/day). We concluded that the propellant sprays create a higher risk of exposure than the pump sprays.

ACS Style

Jihoon Park; Seunghon Ham; Miyeon Jang; Jinho Lee; SunJu Kim; Sungkyoon Kim; Kiyoung Lee; Donguk Park; Jung-Taek Kwon; Hyunmi Kim; Pilje Kim; Kyunghee Choi; ChungSik Yoon. Spatial–Temporal Dispersion of Aerosolized Nanoparticles During the Use of Consumer Spray Products and Estimates of Inhalation Exposure. Environmental Science & Technology 2017, 51, 7624 -7638.

AMA Style

Jihoon Park, Seunghon Ham, Miyeon Jang, Jinho Lee, SunJu Kim, Sungkyoon Kim, Kiyoung Lee, Donguk Park, Jung-Taek Kwon, Hyunmi Kim, Pilje Kim, Kyunghee Choi, ChungSik Yoon. Spatial–Temporal Dispersion of Aerosolized Nanoparticles During the Use of Consumer Spray Products and Estimates of Inhalation Exposure. Environmental Science & Technology. 2017; 51 (13):7624-7638.

Chicago/Turabian Style

Jihoon Park; Seunghon Ham; Miyeon Jang; Jinho Lee; SunJu Kim; Sungkyoon Kim; Kiyoung Lee; Donguk Park; Jung-Taek Kwon; Hyunmi Kim; Pilje Kim; Kyunghee Choi; ChungSik Yoon. 2017. "Spatial–Temporal Dispersion of Aerosolized Nanoparticles During the Use of Consumer Spray Products and Estimates of Inhalation Exposure." Environmental Science & Technology 51, no. 13: 7624-7638.

Conference paper
Published: 01 September 2016 in Oral Session 46 – Biological Exposure Assessment
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Airborne endotoxin and (1-3)-β-D-glucan can cause adverse health problems and lead to potentially occupational exposure to the animal handler in the animal laboratories. The purposes of the study were to assess temporal changes of biological agents concentrations in a laboratory mouse room (LMR) and in a laboratory rabbit room (LRR) and to determine environmental factors associated with endotoxin and (1-3)-β-D-glucan concentrations. The concentrations of airborne endotoxin, and (1-3)-β-D-glucan were sampled once a month in the LMR and LRR. Endotoxin was collected using 3-piece cassettes with a glass fibre filter for six hours and was analysed by the kinetic-turbidimetric Limulus Amebocyte Lysate (LAL) assay. (1-3)-β-D-glucan was performed using two stage cyclone bioaerosol sampler for six hours and assayed using the kinetic chromogenic LAL assay. The endotoxin concentrations did not show large variations, but the concentrations slightly increased in winter for the both rooms. The (1-3)-β-D-glucan concentrations seemed to increase from warmer spring to summer in the LMR and LRR. The overall bioaerosol concentrations were significantly greater in the LRR than in the LMR. The concentrations of bioaerosol in the LMR and LRR varied greatly depending on seasonality, and their changes were affected by the ventilation system and cleaning cycle.

ACS Style

Sung Ho Hwang; Ye Ji Ko; Donguk Park; Seung Hon Ham; Chung Sik Yoon. O46-6 Characteristics of seasonal distribution of airborne endotoxin and (1-3)-β-d-glucan in laboratory animal rooms in seoul, south korea. Oral Session 46 – Biological Exposure Assessment 2016, 73, A88 -A89.

AMA Style

Sung Ho Hwang, Ye Ji Ko, Donguk Park, Seung Hon Ham, Chung Sik Yoon. O46-6 Characteristics of seasonal distribution of airborne endotoxin and (1-3)-β-d-glucan in laboratory animal rooms in seoul, south korea. Oral Session 46 – Biological Exposure Assessment. 2016; 73 ():A88-A89.

Chicago/Turabian Style

Sung Ho Hwang; Ye Ji Ko; Donguk Park; Seung Hon Ham; Chung Sik Yoon. 2016. "O46-6 Characteristics of seasonal distribution of airborne endotoxin and (1-3)-β-d-glucan in laboratory animal rooms in seoul, south korea." Oral Session 46 – Biological Exposure Assessment 73, no. : A88-A89.

Journal article
Published: 26 August 2016 in Safety and Health at Work
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Relationships among portable scanning mobility particle sizer (P-SMPS), condensation particle counter (CPC), and surface area monitor (SAM), which are different metric measurement devices, were investigated, and two widely used research grade (RG)-SMPSs were compared to harmonize the measurement protocols. Pearson correlation analysis was performed to compare the relation between P-SMPS, CPC, and SAM and two common RG-SMPS. For laboratory and engineered nanoparticle (ENP) workplaces, correlation among devices showed good relationships. Correlation among devices was fair in unintended nanoparticle (UNP)-emitting workplaces. This is partly explained by the fact that shape of particles was not spherical, although calibration of sampling instruments was performed using spherical particles and the concentration was very high at the UNP workplaces to allow them to aggregate more easily. Chain-like particles were found by scanning electron microscope in UNP workplaces. The CPC or SAM could be used as an alternative instrument instead of SMPS at the ENP-handling workplaces. At the UNP workplaces, where concentration is high, real-time instruments should be used with caution. There are significant differences between the two SMPSs tested. TSI SMPS showed about 20% higher concentration than the Grimm SMPS in all workplaces. For nanoparticle measurement, CPC and SAM might be useful to find source of emission at laboratory and ENP workplaces instead of P-SMPS in the first stage. An SMPS is required to measure with high accuracy. Caution is necessary when comparing data from different nanoparticle measurement devices and RG-SMPSs.

ACS Style

Seunghon Ham; Naroo Lee; Igchun Eom; Byoungcheun Lee; Perng-Jy Tsai; Kiyoung Lee; ChungSik Yoon. Comparison of Real Time Nanoparticle Monitoring Instruments in the Workplaces. Safety and Health at Work 2016, 7, 381 -388.

AMA Style

Seunghon Ham, Naroo Lee, Igchun Eom, Byoungcheun Lee, Perng-Jy Tsai, Kiyoung Lee, ChungSik Yoon. Comparison of Real Time Nanoparticle Monitoring Instruments in the Workplaces. Safety and Health at Work. 2016; 7 (4):381-388.

Chicago/Turabian Style

Seunghon Ham; Naroo Lee; Igchun Eom; Byoungcheun Lee; Perng-Jy Tsai; Kiyoung Lee; ChungSik Yoon. 2016. "Comparison of Real Time Nanoparticle Monitoring Instruments in the Workplaces." Safety and Health at Work 7, no. 4: 381-388.

Case report
Published: 08 August 2016 in Annals of Occupational and Environmental Medicine
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Bokki Min; Gyuree Kim; Taesun Kang; ChungSik Yoon; Sung-Il Cho; Domyung Paek. IgA nephropathy in a laboratory worker that progressed to end-stage renal disease: a case report. Annals of Occupational and Environmental Medicine 2016, 28, 1 .

AMA Style

Bokki Min, Gyuree Kim, Taesun Kang, ChungSik Yoon, Sung-Il Cho, Domyung Paek. IgA nephropathy in a laboratory worker that progressed to end-stage renal disease: a case report. Annals of Occupational and Environmental Medicine. 2016; 28 (1):1.

Chicago/Turabian Style

Bokki Min; Gyuree Kim; Taesun Kang; ChungSik Yoon; Sung-Il Cho; Domyung Paek. 2016. "IgA nephropathy in a laboratory worker that progressed to end-stage renal disease: a case report." Annals of Occupational and Environmental Medicine 28, no. 1: 1.

Original articles
Published: 12 May 2016 in Journal of Applied Statistics
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Real-time monitoring is necessary for nanoparticle exposure assessment to characterize the exposure profile, but the data produced are autocorrelated. This study was conducted to compare three statistical methods used to analyze data, which constitute autocorrelated time series, and to investigate the effect of averaging time on the reduction of the autocorrelation using field data. First-order autoregressive (AR(1)) and autoregressive-integrated moving average (ARIMA) models are alternative methods that remove autocorrelation. The classical regression method was compared with AR(1) and ARIMA. Three data sets were used. Scanning mobility particle sizer data were used. We compared the results of regression, AR(1), and ARIMA with averaging times of 1, 5, and 10 min. AR(1) and ARIMA models had similar capacities to adjust autocorrelation of real-time data. Because of the non-stationary of real-time monitoring data, the ARIMA was more appropriate. When using the AR(1), transformation into stationary data was necessary. There was no difference with a longer averaging time. This study suggests that the ARIMA model could be used to process real-time monitoring data especially for non-stationary data, and averaging time setting is flexible depending on the data interval required to capture the effects of processes for occupational and environmental nano measurements.

ACS Style

Seunghon Ham; SunJu Kim; Naroo Lee; Pilje Kim; Igchun Eom; Byoungcheun Lee; Perng-Jy Tsai; Kiyoung Lee; ChungSik Yoon. Comparison of data analysis procedures for real-time nanoparticle sampling data using classical regression and ARIMA models. Journal of Applied Statistics 2016, 44, 685 -699.

AMA Style

Seunghon Ham, SunJu Kim, Naroo Lee, Pilje Kim, Igchun Eom, Byoungcheun Lee, Perng-Jy Tsai, Kiyoung Lee, ChungSik Yoon. Comparison of data analysis procedures for real-time nanoparticle sampling data using classical regression and ARIMA models. Journal of Applied Statistics. 2016; 44 (4):685-699.

Chicago/Turabian Style

Seunghon Ham; SunJu Kim; Naroo Lee; Pilje Kim; Igchun Eom; Byoungcheun Lee; Perng-Jy Tsai; Kiyoung Lee; ChungSik Yoon. 2016. "Comparison of data analysis procedures for real-time nanoparticle sampling data using classical regression and ARIMA models." Journal of Applied Statistics 44, no. 4: 685-699.

Journal article
Published: 29 February 2016 in Korean Journal of Environmental Health Sciences
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Seasonal and Environmental Influences on Culturable Airborne Fungi Levels in Microbiology Laboratories Culturable airborne fungi;humidifier;monthly changes;relative humidity;temperature; Objectives: This study aimed to assess temporal changes in the level of culturable airborne fungi (CAF) in three microbiology laboratories and determine the environmental factors associated with CAF level. Methods: CAF levels were determined once per month from March 2011 to February 2012 in three microbiology laboratories. An Andersen one-stage sampler was used for five minutes, three times per day to collect the CAF. Arithmetic means of CAF concentrations and standard deviation (SD) were calculated. A Mann-Whitney test was applied to compare the differences between environmental factors such as divided room by structure of laboratory, use of humidifier, and use of air-conditioner. Correlation analysis was also applied to identify the association between CAF concentrations and environmental factors. Results: CAF levels demonstrated an increasing tendency in summer, and the three laboratories showed consistent seasonal patterns. Temperature and relative humidity (RH) were associated with CAF levels. When the humidifier was off, CAF concentrations were significantly higher in study rooms than in study rooms in which the humidifier was on. Conclusion: CAF levels in indoor microbiology laboratories varied greatly depending upon the temperature and RH and whether a humidifier was used.

ACS Style

Sung Ho Hwang; Sun Yeol Hong; Ji Won Seok; Chung Sik Yoon. Seasonal and Environmental Influences on Culturable Airborne Fungi Levels in Microbiology Laboratories. Korean Journal of Environmental Health Sciences 2016, 42, 19 -26.

AMA Style

Sung Ho Hwang, Sun Yeol Hong, Ji Won Seok, Chung Sik Yoon. Seasonal and Environmental Influences on Culturable Airborne Fungi Levels in Microbiology Laboratories. Korean Journal of Environmental Health Sciences. 2016; 42 (1):19-26.

Chicago/Turabian Style

Sung Ho Hwang; Sun Yeol Hong; Ji Won Seok; Chung Sik Yoon. 2016. "Seasonal and Environmental Influences on Culturable Airborne Fungi Levels in Microbiology Laboratories." Korean Journal of Environmental Health Sciences 42, no. 1: 19-26.