• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.321-327
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• 2009

1,3-butadiene is classified as suspected human carcinogen, group A2(American Conference of Governmental Industrial Hygienists, ACGIH). In Korea, 1,3-butadiene has been used as a raw material; monomer, homopolymer, polybutadiene latex, acrylonitrile-butadiene-styrene(ABS) and styrene-butadiene rubber(SBR), in the petrochemistry and precision chemistry industry. As petrochemistry industry in Korea has been developed, the potential exposure possibility of 1,3-butadiene to workers can be increased. Therefore the purpose of this study is to evaluate airborne 1,3-butadiene concentration and workers' exposure levels in the workplace using 1,3-butadiene. Air samples were collected with 4-tert-butyl catechol(TBC) charcoal tube(100 mg/50 mg) and were analyzed by gas chromatograph/flame ionization detector(GC/FID) according to the Choi's method(2002). Geometric mean (GM) and arithmetic mean (AM) of total 59 workers' exposure concentrations to airborne 1.3-butadiene were 0.042 ppm and 1.51 ppm, respectively. Although most samples were lower than 1ppm, 2 samples(21.5ppm and 33.1ppm as 8hr-TWA) were exceeded the Korean standard(2ppm) over 10 times at the repair process in synthetic rubber and resin manufacture industry. 14 samples(41%) of total 34 short-term air samples were exceeded the Korean standard(10ppm as STEL) of Ministry Labor. 1,3-butadiene concentration(GM) in the synthetic rubber and resin manufacture industry(7.87ppm) was significantly higher than that in the monomer manufacure industry (0.35ppm)(p<0.05). Also in the sampling and repair process, each GM(range) was 1.39ppm(N.D.-469.6ppm) and 7.85ppm(N.D.-410.2ppm). In conclusion, it depends on the industry and process, 1,3-butadiene can be exposed to workers as high concentration for short-term.

• Analytical Science and Technology
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• v.15 no.4
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• pp.381-387
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• 2002

In this study, we introduced experience participated in ELPAT (Environmental Lead for Proficiency Analytical Testing) program that is administered by the American Industrial Hygiene Association and EPA. The 126 sample results of total 128 samples met reference value, as a result accepted 'proficient'. The concentration of Pb in air, paint chips, soils and dust wipes are $0.0089{\sim}0.3956mg/m^3$, 0.0500~8.9149%, 29.0${\sim}$1697 mg/kg and $18.00{\sim}900.3{\mu}g/sample$, respectively. The lead in environmental matrix prepared adequate techniques and analysed by flame atomic absorption spectrometry. The lead in air was extracted hydrochloric acid, in paint chips and soils were digested with microwave and hotplate and in dust wipes were prepared microwave digestion. No differences of each preparation techniques was found and all methods were to be proper.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.87-98
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• 1999

The objectives of this study were to evaluate exposures to airborne methylene chloride and postshift carboxyhemoglobin (COHb) in blood of workers engaged in processes using blowing or cleaning agents, and to investigate correlation between methylene chloride concentrations and the blood COHb levels of workers. The geometric mean (GM) of workers' exposures (8 hour-time weighted averages, TWA) to airborne methylene chloride during cleaning molds using rags wetted with the solvent in the manufacture of flexible polyurethane foam (GM = 61.4 ppm), during operating the dip tank for cleaning molds in the manufacture of lens (GM = 61.0 ppm), and during cleaning the blowing nozzles by spraying the solvent in the manufacture of shoes (GM = 117.2 ppm) were exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value ($TLV^{(R)}$)-Time Weighted Average (TWA) (50 ppm). The COHb levels were significantly different among groups (p<0.05). The average COHh levels in blood of non-smoking workers were 2.0% in. low-level (<50 ppm) exposure group, and 3.9 % in high-level (>50ppm) exposure group. The average COHb levels in smoking workers were 3.1% in low-level exposure group, and 4.8% in high-level exposure group. The blood COHb levels of no-exposed workers to methylene chloride were 1.8% in non-smoking group, and 2.8% in smoking group. It was found that the COHb level dependeds on the methylene chloride concentration and smoking habit, and was highly correlated with methylene chloride concentration in air. The correlation coefficient was 0.81 among non-smoking workers. The estimated COHb level (3.6%) and 95% upper confidence limit (4.0%) corresponding to TLV-TWA of methylene chloride exceeded the current ACGIH Biological Exposure Index (COHb 3.5%) for carbon monoxide. The estimated COHb level (5.4%) at 100 ppm exceeded the standard (5%) recommended by National Institute for Occupational Safety and Health (NIOSH) for preventing adverse cardiovascular effect. The estimated COHb value and 95% upper confidence limit at 25 ppm of the Occupational Safety and Health. Adminstration (OSHA) Permissible Exposure Limit-TWA (PEL-TWA) were 2.6% and 3.0%, respectively. It is suggested that COHb in blood be kept below 3.0% to comply with OSHA PEL-TWA.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.2
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• pp.153-159
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• 2007

Usually equal noise exposure is considered to cause symmetrical hearing loss, but some screening audiometries of employees who were exposed to noise showed asymmetry. Therefore, this study was carried out to evaluate the distribution of asymmetrical hearing loss and the difference of air conduction level between left and right ear at the different frequencies (500, 1,000, 2,000, 3,000, 4,000, 6,000 Hz). Study subjects were 326 male employees who had participated in the noise-specific health examination from May to October, 2002. They were evaluated by otoscopic examination, pure tone audiometry and tympanometry. In all frequencies, hearing threshold level of left ear was worse than right ear. The mean interaural threshold differences between two ears were 0.83 dB at 500 Hz, 1.18 dB at 2,000 Hz, 2.29 dB at 3,000 Hz, 2.18 dB at 4,000 Hz, and statistically significant (p<0.05). The hearing loss of left ear was greater than right ear in occupationally noise-exposed workers. It is believed that left ear was more susceptible to noise damage than right ear

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.2
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• pp.159-169
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• 2016

Objectives: The objective of this study was to evaluate the generating characteristics of VOCs and the exposure effect to chemicals among laundry workers and to identify the current status of occupational safety and health through health check-ups. Methods: During the six-month period from April to September 2015, this study quantitatively measured seven VOCs in ten laundries and carried out health examinations on 35 workers. Results: Comparing the monitoring results for the ten laundries, they were classified into three groups by ventilation system, dry-cleaning and size of shop. The average concentration of toluene, chlorobenzene, xylene, ethylbenzene, benzene, styrene and TCE were 23.9, 15.6, 5.5, 2.8, 0.9, 0.3 and $1.3{\mu}g/m^3$, respectively. During dry-cleaning, VOC concentrations were 1.3-8.9 times higher than usual. On the other hand, at night the concentrations of toluene, chlorobenzene, xylene, ethylbenzene, benzene, styrene and TCE were 64.3, 41.5, 12.2, 6.3, 1.1, 1.2 and $6.6{\mu}g/m^3$, respectively. The health checkup results for the 35 workers showed that 13 workers were diagnosed as normal, while 22 workers were diagnosed as requiring continuous monitoring or re-checkup of liver and hematogenous functions. Conclusions: Although the results of exposure evaluation to VOCs did not exceed reference value and items had a low correlation with health checkup items, it is necessary to improve indoor air quality due to VOC volatilization from clothes.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.2
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• pp.225-236
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• 2016

Objectives: Nanomaterials have been used in various fields. As use of nanoproducts is increasing, workers dealing with nanomaterials are also gradually increasing. Exposure assessments for nanomaterials have been carried out for protection of worker's health in workplace. Exposure studies were mainly focused on manufacturing processes, but these studies on after-treatment processes such as refinement, weighing, and packing were insufficient. So, we investigated exposure characteristics of particles during after-treatment processes of $Al_2O_3$ fibers and Ni powders. Methods: Mass-production of Ni powder process was carried out in enclosed capture-type canopy hood. In a developing stage, $Al_2O_3$ was handled with a local ventilation unit. Exposure characteristics of particles were investigated for $Al_2O_3$ fiber and Ni powder processes during the periods of 10:00 to 16:00, 20 May 2014 and 13:00 to 16:00, 21 May 2014, respectively. Three real-time aerosol instruments were utilized in exposure assessment. A scanning mobility particle sizer(SMPS, nanoscan, model 3910, TSI) and an optical particle counter(OPC, portable aerosol spectrometer, model 1.109, Grimm) were used to determine the particle size distribution in the size range of 10-420 nm and $0.25-32{\mu}m$, respectively. In addition, a nanoparticle aerosol monitor(NAM, model 9000, TSI) was used to measure lung-deposited nanoparticle surface area. Membrane filters(isopore membrane filter, pore size of 100 nm) were also used for air sampling for the FE-SEM(model S-5000H, Hitachi) analysis using a personal sampling pump(model GilAir Plus by 2.5 L/min, Gilian). Conclusions: For Ni powder after-treatment process, only 27% increase in particle concentration was found during the process. However, for $Al_2O_3$ fiber after-treatment process, significant exposure(1.56-3.34 times) was observed during the process.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.310-320
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• 2014

Backgrounds: Endotoxin, which found in the outer membrane of the gram-negative bacteria cell wall, makes up almost all of the lipopolysaccharide(LPS). When people are exposed to endotoxin,it can result in diverse health effects such as an airway irritation and inflammation, fever, malaise, bronchitis, allergic asthma, toxic pneumonitis, hypersensitivity lung disease. Cases among the elderly, children or pregnant can occur more frequently than a healthy adult if they are repeatedly exposed to the existing endotoxin. Therefore, we investigated and assessed the environmental characteristics associated with the airborne endotoxin concentration level in six hospital lobbies. Method: Endotoxin from indoor air in six hospital lobbies was measured by an area sampling method and analyzed according to American Society for Testing and Materials International(ASTM international) E2144-01. Total suspended particulate(TSP), carbon dioxide($CO_2$), temperature and humidity were also measured by using direct reading measurements or airborne sampling equipment at the same time. Environmental characteristics were appropriately divided into two or three groups for a statistics analysis. One-way analysis variable(one-way ANOVA) was used to examine a difference of the endotoxin concentration, depending on the environmental characteristics. In addition, only variables with p-value(p<0.25) were eventually designed to the best model by using multiple regression analysis. Results: The correlation analysis result indicated that TSP(p=0.003) and $CO_2$(p<0.0001) levels were significantly associated with endotoxin concentration levels. In contrast, temperature(p<0.068) and humidity(p<0.365) were not associated with endotoxin concentration. Levels of endotoxin concentration were statistically different among the environmental characteristics of Service time(p=0.01), Establishment of hospital(p<0.001), Scale of hospital(p=0.01), Day average people using hospital(p=0.03), Cleaning time of lobby(p=0.05), Season(p<0.001), and Cleaning of ventilation system(p<0.001) according to ANOVA. Finally, the best model(Adjusted R-square=72%) that we designed through a multiple regression test included environmental characteristics related to Service time, Area of lobby, Season, Cleaning of ventilation system, and Temperature. Conclusions: According to this study, our result showed a normal level of endotoxin concentration in the hospital lobbies and found environmental management methods to reduce the level of endotoxin concentration to a minimum. Consequently, this study recognized to be requirement for the management of ventilation systems and an indoor temperature in order to reduce the level of endotoxin concentration in the hospital lobbies.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.1
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• pp.38-45
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• 2014

본 연구에서는 기계환기에 의한 실내공기질 개선효과를 현장실험을 통해 파악하기 위해 환기설비를 갖춘 A 신축아파트와 다중이용시설인 B 백화점을 연구 대상으로 하였다. A 신축아파트에서는 새집증후군 등 주요 실내공기오염의 원인물질인 VOCs 및 HCHO를 측정 대상물질로 선정하고 미환기 상태에서 16가구에서 전반적인 신축아파트의 실내공기오염 특성을 파악하였으며, 이중 상대적으로 TVOC 농도가 높은 2가구를 대상으로 환기전후의 농도 특성을 파악하였다. B 백화점에서는 $CO_2$ 및 HCHO를 대상물질로 선정하고 1~7층별로 미환기시와 기계환기 1시간 이후의 농도 특성을 통해 환기에 의한 저감율을 파악하였으며, 이후 환기시설 정상가동 상태에서 3년간 실내공기오염물질의 농도 특성을 파악하였다. 미환기 상태에서 A 신축아파트의 VOCs 및 HCHO 농도는 일부 지점에서는 에틸벤젠, 자일렌 등의 농도가 실내환경기준을 초과하고 있었다. 특히 환기전후의 TVOC 농도 특성은 A-1 지점의 경우 미환기시 $3,547{\mu}g/m^3$에서 환기시 $961{\mu}g/m^3$ 그리고 A-2 지점의 경우 미환기시 $3,117{\mu}g/m^3$에서 환기시 $594{\mu}g/m^3$으로 환기에 의해 각각 73%, 81% 저감율이 나타났다. 또한 개별 VOCs 및 HCHO물질별 환기에 의한 저감율은 31.4~96.7%로 나타났으며, 환기이후 모든 물질이 실내기준보다 훨씬 낮은 수준으로 나타났다. B 백화점에서는 평균 $CO_2$ 농도는 미환기시 855 ppm에서 기계환기 1시간 이후 580 ppm으로 약 32% 저감되었으며, HCHO의 평균농도도 $251{\mu}g/m^3$에서 $70.3{\mu}g/m^3$으로 약 72%의 저감되는 것으로 나타났다. 이후 환기시설 정상가동 상태에서 3년간 실내공기질의 측정결과 지속적으로 실내환경 기준을 만족하였다. 최근 실내공기질 개선을 위해 다양한 개선 방법이 소개되고 있으나, 이중 기계환기는 신축아파트 및 다중이용시설 등에서 실내공기질을 실내환경기준 이하로 지속적이고 쾌적하게 유지할 수 효과적 방법으로 고려된다.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.398-422
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• 2017

Objectives: The major aim of this study is to construct the database of retrospective exposure assessment for crystalline silica through reviews of literatures in South Korea. Methods: Airborne concentrations of crystalline silica were collected using an academic information search engine, Research Information Service System(RISS), operated by the Korea Education & Research Information Service(KERIS). The key words used for the literature search were 'silica', 'crystalline silica', 'cristobalite', 'quartz' and 'tridymite'. A total number of 18 published documents with the information of crystalline silica level in air or bulk samples were selected and used to estimate retrospective exposures to crystalline silica. Weighted arithmetic mean(WAM) calculated across studies was summarized by industry type. Industries were classified according to Korea Standard Industrial Classification(KSIC) using information provided in the literature. Results: A total of 2,131 individual air sampling data measured from 1987 to 2012 were compiled. Compiled individual measurement data consisted of 827 respirable crystalline silica (RCS), 31 total crystalline silica(TCS), 24 crystalline silica(CS), 778 respirable dust(RD) and 471 total dust(TD). Most of RCS measurements(68.9%) were collected from 'cast of metals(KSIC 243)'. Comparing industry types, 'mining coal and lignite(KISC 051)' showed the highest WAM concentration of RCS, $0.14mg/m^3$, followed by $0.11mg/m^3$ of 'manufacture of other non-metallic mineral products(KSIC 239)', $0.108mg/m^3$ of 'manufacture of ceramic ware(KSIC 232)', $0.098mg/m^3$ of 'heavy construction(KSIC 412)' and $0.062mg/m^3$ of 'cast of metals(KSIC 243)'. In terms of crystalline silica contents in airborne dust, 'manufacture of other non-metallic mineral products(KSIC 239)' showed the highest value of 7.3%(wt/wt), followed by 6.8% of 'manufacture of ceramic ware(KSIC 232)', 5.8% of 'mining of iron ores(KSIC 061)', 4.9% of 'cast of metals(KSIC 243)' and 4.5% of 'heavy construction(KSIC 412)'. WAM concentrations of RCS had no consistent trends over time from 1994 ($0.26mg/m^3$) to 2012 ($0.12mg/m^3$). Conclusion: The data set related RCS exposure level by industries can be used to determine not only the possibility of retrospective exposure to RCS, but also to evaluate the level of quantitative retrospective exposure to RCS.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.2
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• pp.205-212
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• 2020

Objectives: The purpose of this study was to identify the needs and improvement measures of the risk assessment system through a survey of asbestos abatement companies. Methods: This study prepared a questionnaire that includes improvement measures for the risk assessment system(six questions) and the necessity of a risk assessment system for asbestos abatement(one question). The questionnaire was sent to 2,170 asbestos abatement companies and returned by 83 companies(return rate = 3.8%). We conducted frequency analysis, ANOVA, and Chi-squared testing at the 5% significance level. Results: This study analyzed the survey results and identified six main opinions on the risk assessment system and improvement measures. First, giving an advantage to companies with a high grade(S and A grades) in public bidding and/or qualification screening showed a similar preference(agree: 50.6%, disagree: 49.4%). Second, 57.6% of the respondents wanted to allow air showers along with water showers for low risk asbestos work. However, 23.2% of the respondents asserted that only a water shower should be allowed since there is no scientific evidence supporting the removal of asbestos by air shower. Third, in order to prevent missing the enrollment of workers, simply submitting a change report should be allowed when any worker is changed (40.0%). Fourth, 43% of the respondents answered that they did not know how to calculate the proper number of negative pressure units. The reasons given were a lack of guidelines or standards(38.9%), inconvenience (36.1%), and absence of education(25%). Fifth, the respondents who were favorable toward the necessity of a risk assessment system gave higher scores compared to unfavorable respondents on the necessity of the management of workers' work history(favorable respondent = 3.96 out of 5, unfavorable respondent = 2.68) and the necessity of professional training for workers(favorable respondent = 3.71, unfavorable respondent = 2.56). Finally, the respondents favorable toward a risk assessment system showed higher scores on the awareness of calculating the proper number of negative pressure units(4.79) compared to unfavorable respondents(3.3). Conclusions: The opinions of asbestos abatement companies identified through the survey in this study can be usefully utilized as fundamental information to improve the risk assessment system.