• 한국산업보건학회지
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• 제22권2호
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• pp.119-127
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• 2012

Objectives: The aim of this study is to identify concentration characteristics of indoor and outdoor airborne total fiber particles and asbestos in Gyeongnam Provinces. Methods: This study investigated concentration characteristics of indoor fiber particles from 748 schools and 38 public facilities as well as outdoor particles from 11 sites through PCM (phase contrast microscope). SEM/EDX (scanning electron microscope/energy dispersive using X-ray analysis) was used to obtain physicochemical information of asbestos fiber particles. The study identified asbestos rate in the 15 samples from indoor and outdoor airborne total fiber particles. Results: 1. The average indoor airborne concentrations of total fiber particles were $0.0011{\pm}0007$ f/cc in schools and $0.0015{\pm}0007$ f/cc in public facilities by PCM. Over 90% of the fiber particles were identified as single fibers. 2. The average outdoor airborne concentrations of total fiber particles were $0.0007{\pm}0002$ f/cc, and they were lower than those of indoor airborne concentrations. 3. The results showed that the form of asbestiform was diverse as skein of thread like form and long needle, which was relatively narrower than that of glass fiber and rock wool. 4. The results of SEM/EDX analysis of 15 areas where total fiber particle was relatively high showed that the form was rather similar to that of asbestos, but chemical composition was proven to be non-asbestos. Conclusions: The concentration of indoor and outdoor airborne total fiber particles of Gyeongnam Provinces satisfied the IAQ (Indoor air quality) level of 0.01 f/cc and asbestos was not found in most of the samples by SEM/EDX.

• Safety and Health at Work
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• 제14권2호
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• pp.215-221
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• 2023

Background: There is little information about the airborne hazardous agents released during the heat treatment when manufacturing a welding material. This study aimed to evaluate the airborne hazardous agents generated at welding material manufacturing sites through area sampling. Methods: concentration of airborne particles was measured using a scanning mobility particle sizer and optical particle sizer. Total suspended particles (TSP) and respirable dust samples were collected on polyvinyl chloride filters and weighed to measure the mass concentrations. Volatile organic compounds and heavy metals were analyzed using a gas chromatography mass spectrometer and inductively coupled plasma mass spectrometer, respectively. Results: The average mass concentration of TSP was 683.1±677.4 ㎍/m³, with respirable dust accounting for 38.6% of the TSP. The average concentration of the airborne particles less than 10 ㎛ in diameter was 11.2-22.8×10⁴ particles/cm³, and the average number of the particles with a diameter of 10-100 nm was approximately 78-86% of the total measured particles (<10 ㎛). In the case of volatile organic compounds, the heat treatment process concentration was significantly higher (p < 0.05) during combustion than during cooling. The airborne heavy metal concentrations differed depending on the materials used for heat treatment. The content of heavy metals in the airborne particles was approximately 32.6%. Conclusions: Nanoparticle exposure increased as the number of particles in the air around the heat treatment process increases, and the ratio of heavy metals in dust generated after the heat treatment process is high, which may adversely affect workers' health.

• 한국환경보건학회지
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• 제46권6호
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• pp.757-763
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• 2020

Objectives: The objective of this study was to evaluate the concentrations of airborne fungi in public transportation from autumnl 2016 to summer 2017. Methods: This study measured the concentrations of airborne fungi on six subway lines and intercity buses in Seoul. Results: The concentration of fungi in the air in public transportation was found to be lower than the standard (500 CFU/㎥) for vulnerable group facilities among public use facities. In summer, the concentration of airborne fungi was relatively higher than in autumn. The concentrations of airborne fungi in subway (252.0 CFU/㎥) and train (45.1 CFU/㎥) were high tendency during non-rush hours in summer, while intercity bus was hightendency during rush hours in summer (111.9 CFU/㎥). The major types of airborne fungi in public transportation were Cladosporium, Penicillium, and Aspergillus. Conclusions: The harmful airborne fungus were detected though they did not exceed the standard in all public transportation. As a result, further studies on the analysis of the distribution of airborne fungi by ventilation and the characterization of indoor environments are needed to propose effective management of airborne fungi in public transportation.

• 한국환경보건학회지
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• 제33권4호
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• pp.250-254
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• 2007

The reduction efficiency of air cleaner on particulate contaminants such as dust, airborne bacteria and fungi distributed in the office was relatively higher in case of office with workers than office without workers. This result would be attributed to workers' activities and physical characteristics of particulate contaminants. The air cleaner decreased a concentration of airborne bacteria more than airborne fungi, which implicates that difference of dust adsorption between airborne bacteria and fungi would affect an operation efficiency of air cleaner.

• 한국대기환경학회지
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• 제25권6호
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• pp.493-502
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• 2009

The concentrations of outdoor airborne bacteria measured in Seoul, Korea for one year (Jan. 2008~Dec. 2008) ranged from $500CFU/m^3$ to $7,500CFU/m^3$. In monthly concentration distribution, the level of outdoor airborne bacteria was highest in September and October and lowest in March. In seasonal concentration distribution, the order of level of outdoor airborne bacteria was autumn>winter>spring>summer. In regional concentration distribution, the highest level of outdoor airborne bacteria was generally found in the forest, followed by general area and traffic site. In distribution characteristics according to particle size, outdoor airborne bacteria showed 31% for >$7.0{\mu}m$ (stage 1), 21% for $4.7{\sim}7.0{\mu}m$(stage 2), 15% for $3.3{\sim}4.7{\mu}m$(stage 3), 19% for $2.1{\sim}3.3{\mu}m$(stage 4), 10% for $1.1{\sim}2.1{\mu}m$(stage 5), and 4% for $0.65{\sim}1.1{\mu}m$(stage 6) and its mean respirable fraction was 48%. In concentration distribution by yellow dust, the mean levels of outdoor airborne bacteria were 803 $(\pm479)CFU/m^3$ for period of yellow dust and 691 $(\pm1,134)CFU/m^3$ for period of non-yellow dust. Although the level of outdoor airborne bacteria was higher in period of yellow dust than period of non-yellow dust, there was no significant difference between period of yellow dust and non-yellow dust (p>0.05). In correlation analysis between outdoor airborne bacteria and atmospheric factors (temperature and relative humidity), there was no significant correlation between outdoor airborne bacteria and atmospheric factors. The predominant airborne bacteria were identified to the Bacillus-derived species.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.842-845
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• 2004

When the concrete structures are in contact with seawater, concentration of chloride for estimating chloride diffusion coefficient can be defined as the chloride concentration of sea water. However, in case the concrete structures, constructed in the seashore, aren't directly in contact with seawater, it is difficult to establish the interface concentration of chloride. In addition, marine concrete structures are greatly affected by salt attack such as rebar corrosion, among the cause of salt attack, airborne sea salt is primary factor. Therefore, in this study, salt attack environment by airborne sea salt was investigated in terms of the distance from seashore at 33 spots, 6 areas in East, West, South coast for 1 year. Results indicated that airborne sea salt is decreased by $y=a{\cdot}x^{-b}$ equation to the distance from seashore.

• 대한의생명과학회지
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• 제11권2호
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• pp.143-152
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• 2005

To investigate the exposure effect of polycyclic aromatic hydrocarbons (PAHs), we analyzed the relationship between urinary 8-hydroxydeoxyguanosine (8-OHdG) concentration and PAHs exposure. The study population contained 44 workers in steel-pipe coating and paint manufacture industries. We measured airborne total PAHs as an external dose, urinary 1-hydroxypyrene (1-OHP) as an internal dose of PAHs exposure, and urinary 8-OHdG as an effective dose of oxidative DNA damage. There was significant correlation between the urinary concentration of l-OHP and the environmental concentration of PAHs, pyrene, urinary cotinine, AST, and GGT. The mean of urinary 8-OHdG was $17.07\pm1.706{\mu}g/g$ creatinine in workers exposed to airborne PAHs. There was significant correlation between the urinary concentration of 8-0HdG and the airborne concentration of PAHs. From the results of stepwise multiple regression analysis about 8-OHdG, significant independents was total PAHs. In this study, there were significant correlation between the urinary concentration of 8-OHdG and the airborne concentration of PAHs. The urinary 1-OHP was effective index as a biomarker of airborne PAHs in workplace. But it was influenced by non-occupational PAHs source, smoking and biomarkers of liver function test.

• 한국환경보건학회지
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• 제26권4호
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• pp.21-28
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• 2000

Various man-made mineral fibers(MMMF) including refractory ceramic fiber(RCF) have been used widely in industries as insulation materials. The effect of fibrous dust on human health depends on fiber size, concentration (exposure level), and durability in biological system. Therefore, these parameters should be determined to evaluate accurately the potential risk of fibers on human health. The purpose of this study was to characterize the size of airborne fiber and the workers＇ exposure to airborne fibers in refractory ceramic fiber manufacturing and processing factories. Airborne fibers were collected on 25-mm mixed cellulose ester membrane filters at personal breathing zones, and analyzed by A and B counting rules of the National Institute for Occupational Safety and Health(NIOSH) Method # 7400. The average ratios of the fiber density by B rule to the fiber density by A rule was 0.84. This result indicates that the proportion of respirable fibers (<3 ${\mu}{\textrm}{m}$ diameter) in air samples was high. The average diameter and length of airborne fibers were 1.05${\mu}{\textrm}{m}$ and 35${\mu}{\textrm}{m}$, respectively. The average fiber concentrations (GM) of all personal samples was 0.26f/cc, and the average concentration was highest at blanket cutting and packing processes. The fifty seven percent of personal air samples was exceeded the proposed American Conference of Governmental Industrial Hygienists(ACGIH) Threshold Limit Value(TLV), i.e. 0.2 f/cc. It was concluded that the RCF industrial workers had the higher potential health risk due to small fiber diameter, long fiber length, and high exposure level to the airborne fibers.

• Journal of Preventive Medicine and Public Health
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• 제39권4호
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• pp.325-330
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• 2006

Objectives: The aims of this study were to examine the level of airborne fungi and environmental factors in Seoul metropolitan subway stations and to provide fundamental data to protect the health of subway workers and passengers. Methods: The field survey was performed from November in 2004 to February in 2005. A total 22 subway stations located at Seoul subway lines 1-4 were randomly selected. The measurement points were subway workers' activity areas (station office, bedroom, ticket office and driver's seat) and the passengers' activity areas (station precincts, inside train and platform). Air sampling for collecting airborne fungi was carried out using a one-stage cascade impactor. The PM and CO2 were measured using an electronic direct recorder and detecting tube, respectively. Results: In the activity areas of the subway workers and passengers, the mean concentrations of airborne fungi were relatively higher in the workers' bedroom and station precinct whereas the concentration of particulate matter, $PM_{10}\;and\;PM_{2.5}$, were relatively higher in the platform, inside the train and driver's seat than in the other activity areas. There was no significant difference in the concentration of airborne fungi between the underground and ground activity areas of the subway. The mean $PM_{10}\;and\;PM_{2.5}$ concentration in the platform located at underground was significantly higher than that of the ground (p<0.05). Conclusions: The levels of airborne fungi in the Seoul subway line 1-4 were not serious enough to cause respiratory disease in subway workers and passengers. This indicates that there is little correlation between airborne fungi and particulate matter.

• 한국산업보건학회지
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• 제20권4호
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• pp.248-255
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• 2010

Airborne nanoparticle concentrations in three metrics (particle surface area concentration, particle number concentration, and particle mass concentrations) were measured by task in a laboratory making carbon nanotubes (CNTs) films using three direct reading instruments. Because of the conducted other researcher's experiment before the tasks, airborne nanoparticle surface area and number concentrations are the highest at the first time conducted weighing and mixing by sonication task, respectively. Because of the mist generated during mixing by sonication, the highest airborne nanoparticle surface area and PM1 concentrations were measured in the task among the total. Nanoparticle surface area concentrations at the researchers' breathing zones had high correlation (r=0.93, p<0.01) with those measured at an area in the laboratory. This result indicates that nanoparticles generated during the experiment contaminated the whole room air. When the experiment performed all the fume hoods weren't operated and making CNTs films task were conducted in the out of the fume hoods. In conclusion, researchers performing making CNTs film experiments were exposed to airborne nanoparticles generated during the experiment without adequate controls. We recommend that adequate controls should be implemented so that workers' exposures to airborne nanoparticle are limited to minimum levels.