• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.23 no.3
• /
• pp.196-204
• /
• 2013

Objectives: The purpose of this study is to analyze the number and influence factors of asbestos fibers in the air of farmhouses with asbestos cement slate roofing, as well as in rainwater per unit area of the asbestos cement slate roofing. Methods: At a distance of 1 m from the end of asbestos cement slate roofing in 20 farmhouses, the asbestos fiber in the air was collected three times on a clear day downwind from the prevailing wind. Rainwater falling from the slate roofing was collected four times with a 1.05-m rainwater pipe on a rainy day at the 20 farmhouses, filtered with a MCE filter, and analyzed with a phase contrast microscope. Results: The geometric mean of the number of asbestos fibers in the air of farmhouses with slate roofing was 0.11 fiber/L, and no samples exceeded the recommended standard of 10 fiber/L. As a result of multiple regression analysis, a factor which gave a significant influence to the asbestos fiber content in the air was the gross area of slate roofing at the target farmhouses. The number of asbestos fibers included in rainwater collected per 1 m2 of slate roofing was 1,753 fiber/$L{\cdot}m2$. As a result of multiple regression analysis, the number of asbestos fibers contained in rainwater per 1 m2 of slate showed a significantly higher tendency as the year of slate roofing installation at the target farmhouses receded. Conclusions: It was confirmed for the first time in Korea that asbestos from asbestos cement slate roofing scatters into the air.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.25 no.2
• /
• pp.174-183
• /
• 2015

Objectives: The objective of this study is the estimation of factors influencing airborne fiber concentrations by means of an observation survey of asbestos-containing materials in buildings. Methods: Forty-five samples were collected from four commercial buildings by NIOSH Method 7400 and classified according to current condition, potential activity, construction year, and operations and maintenance(O&M). Results: Airborne fiber concentrations by current condition(classified as good, fair and poor) were significantly different(p<0.05). Concentrations by potential activity were significantly different among groups(p<0.05), and those from the low activity group were higher than those from the middle activity group. Based on construction year, airborne fiber concentrations from the decade of the 1990's were higher than those from the 1960's. When O&M status was considered, airborne fiber concentrations from 1960's buildings were lower than those buildings not operated and maintained(p<0.01), because dust generation was influenced by O&M status. It was found that airborne fiber concentrations were related to current condition and potential activity via regression analysis, but the coefficient of determination was low. Also, correlation analysis showed that the higher the potential activity, the more current condition is worsened, but the relationship was not significant(r=-0.455, p>0.05). Conclusions: Airborne fiber concentrations in asbestos-containing buildings had weak relationships with current condition and potential activity.

• Analytical Science and Technology
• /
• v.22 no.5
• /
• pp.369-375
• /
• 2009

We evaluated the homogeneity and accuracy of low level airborne fibrous standard, and accomplished the proper proficiency test. We had found that the correlation of concentration of standard solution and asbestos density was 0.9863~0.9968, and concluded that the proper guideline of the analysis result was ${\mid}Z{\mid}{\leq}2$ interval of Z-score.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.5
• /
• pp.17-25
• /
• 2016

In this study, the air quality of underground and overground railway stations was evaluated focusing on the degree of influence of the outside air quality. The measured components were particulate matter ($PM_{10}$), carbon dioxide ($CO_2$), carbon monoxide (CO), nitrogen dioxide ($NO_2$), formaldehyde (HCHO), ozone ($O_3$), total airborne bacteria (TAB), total volatile organic carbon (TVOC), and Radon (Rn), which are included in the maintenance standards and recommended standards of the Indoor Air Quality Management Act. Also, the indoor/outdoor concentration ratios of $PM_{10}$, $NO_2$, and $O_3$ were calculated to estimate the influence of the outdoor air quality. The concentrations of $PM_{10}$ HCHO, TVOC, $NO_2$, and Rn in the underground stations were found to be higher than those in the overground stations. These results indicate that the (present) generation of contaminants are caused by the indoor source of the underground station. The ozone concentration of the overground stations was higher than that of the underground stations, which indicates that the outdoor ozone concentration influenced that of the overground stations directly. Thus, methods of improving the IAQ should take into consideration the types of contamination.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.5 no.1
• /
• pp.16-39
• /
• 1995

From July 8 to September 2 1994, asbestos exposure level among asbestos textile workers was surveyed. Six plants out of plants in Korea were selected for this study. In addition to the exposure level, the relationship between the level of exposure and some factors affecting exposure were studied. Also, using historical data of asbestos concentrations in asbestos textile plants plus current data, trend of asbestos exposure level could be introduced. Historical exposure level was estimated on the basis of these data. The main results of this study are follows. 1. Average concentration of all six plants surveyed was 1.54 f/cc, and range of those concentrations was 0.03 - 11.58 f/cc. The minimum average concentration was 0.32 f/cc and the maximum was 8.04 f/cc which is four times higher than the Korean standard. A wide difference of exposure level among the workers of different plants was observed. In three plants, the half of all the plants surveyed, their average concentrations exceeded the Korean standard, and those in all the plants exceeded the ACGIH TLV. 2. Among total 56 samples, 22 samples(39%) were in excess of the Korean standard, and 53 samples(95%) were above the ACGIH TLV. Among 32 personal samples, 15 samples(47%) exceeded the Korean standard, and 30 samples(94%) exceeded the ACGIH TLV. Among 24 area samples excluding a few samples collected in office area, seven samples exceeded the Korean standard, and 23 samples( 96%) exceeded the ACGIH TLV. 3. Distributions of concentrations were observed by processes. In weaving, the highest, average concentration was 4.29 f/cc, and range was 2.61 - 11.58 f/cc. In spinning, average concentration was 2.22 f/cc, and range was 0.41 - 8.93 f/cc. In carding, average concentration was 1.98 f/cc, and range was 0.23 - 10.93 f/cc, In twisting, average concentration was 1.65 f/cc, and range was 0.21 - 9.83 f/cc. In mixing, the lowest, average concentration was 0.48 f/cc, and range was 0.22 - 1.20 f/cc. 4. All the samples from basic processes of asbestos textile plants were above the ACGIH TLV. Nineteen samples(45%) out of all these 42 samples exceeded Korean standard. Fourteen samples(58%) of total 24 personal samples, and five samples(28%) of total 18 area samples exceeded the Korean standard. Considering processes, all the samples in weaving process exceeded the Korean standard and 50 did 54% of those in spinning, 40% in carding, and 27% in twisting. 5. Trend of decreasing asbestos concentrations in asbestos textile plants was observed by time. 6. Asbestos concentrations in asbestos textile plant in 1975 were estimated to be 11.0 - 92.4 f/cc.

• Korean Journal of Microbiology
• /
• v.39 no.1
• /
• pp.16-20
• /
• 2003

A phylogenetic analysis of bacterial populations inhabiting soil derived from serpentine was conducted. The samples were collected from adjacent metamorphic rocks and serpentinite soil at Kwangcheon. The pH of the serpentine areas ranged from 8.5 to 9.2. The number of bacteria on the DAL medium which was diluted with $10^{-2}$ of AL medium was 10~100 fold higher than that from the full strength of AL medium, and which indicates that oligotrophs are distributed in the serpentinite soil. Of a total of 76 isolates, 42 isolates were oligotrophic bacteria, which grew only on the DAL medium. Based on a phylogenetic analysis using 16S rDNA sequences, these isolates are found to fall within five major phylogenetic groups: proteobacteria $\alpha$-subdivision (3 strains), $\alpha$-subdivision (7 strains), $\gamma$-subdivision (2 trains); high G+C gram-positive bacteria (19 strains); low G+C grampositive bacteria (14 strains). Bacteria of the genus Streptomyces (high G+C division) and Bacillus (low G+C division) have been considered to form a numerically important fraction of serpentinite soil. Oligotrophic strains categorized as Afipia ($\alpha$-subdivision), Ralstonia, Variovorax ($\beta$-subdivision), Pseudomonas ($\gamma$ -subdivision), Arthrobacter (high G+C division), and Streptomyces (low G+C division).

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.1 no.2
• /
• pp.221-237
• /
• 1991

This study was conducted to evaluate the accuracy and the precision of asbestos counting data produced by the Division of Industrial Health, School of Public Health, Seoul National Universitys (SNU). The study was performed from July 18 to October 4, 1991, and the results are summarized as follows. 1. Intracounter Relative Standard Deviations (Sr) in the category of 5-50.5 fibers as total fibers counted ranged from 0.27 to 0.37, which were greater than 0.10-0.17 which were reported by the NIOSH. The reasons are supposed to be as follows. First, inexperience of counters in asbestos fiber counting was considered to be a main reason. Second, poor quality of samples due to sampling and mounting error increased variation of counting. Third, fiber density of many samples were less than $100fibers/mm^2$. But Intracounter Relative Standard Deviations (Sr) in samples with >50.5 fibers ranged from 0.l6 to 0.20, approaching the value 01 NIOSH. 2. Intralaboratory Relative Standard Deviations (Sr) in categories of 5-20.5, >20.5-50.5 and >50.5 fibers were 0.54, 0.37 and 0.26, respectively. Intralaboratory Sr in samples with fiber density greater than $100fibers/mm^2$ was 0.26. This was similar to the values reported by other foreign experienced laboratories. 3. Comparing results of three counters, Counter C, a beginner, overestimated asbestos fiber concentrations. 4. Since our SNU laboratory has participated in two quality control programs, IOMA-F.R.I.C.A., U.K. and NIOSH PAT Program, U.S.A., this laboratory has been evaluated as " Rating 1" and "Proficient" laboratory, by IOM and NIOSH, respectively.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.22 no.2
• /
• pp.119-127
• /
• 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.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.24 no.2
• /
• pp.113-121
• /
• 2014

Objectives: This study is intended to seek credible and efficient measurements on airborne asbestos concentrations that allow immediate action by establishing complementary data through comparative analysis with existing PCM and KF-100 method real-time monitoring equipment in working areas in Seoul where asbestos-containing buildings are being demolished, including living environment surroundings. Materials: We measured airborne asbestos concentrations using PCM and KF-100 at research institutes, monitoring networks, subway stations and demolition sites of asbestos-containing buildings. Through this measurement data and KF-100 performance testing, we drew a conversion factor and applied it via KF-100. Finally we verified the relationship between PCM and KF-100 with statistical methods. Results: The airborne asbestos concentrations by PCM for the objects of study were less than the detection limit(7 fiber/$mm^2$) in three (20%) out of 15 samples. The highest concentration was 0.009 f/cc. The airborne asbestos concentrations by PCM in laboratories, monitoring networks, subway stations and demolition sites of asbestos-containing buildings were respectively $0.002{\pm}0.000$ f/cc, $0.004{\pm}0.001$ f/cc, $0.009{\pm}0.001$ f/cc, and $0.002{\pm}0.000$ f/cc. As a result of KF-100 performance testson rooftops, the conversion factor was 0.1958. Applying the conversion factor to KF-100 for laboratories, the airborne asbestos concentrations ratio of the two ways was nearly 1:1.5($R^2$=0.8852). Also,the airborne asbestos concentration ratio of the two ways was nearly 1:1($R^2$=0.9071) for monitoring networks, subway stations, and demolition sites of asbestos-containing buildings. As a result of independent sample t-tests, there was no distinction between airborne asbestos concentrations monitored in the two ways. Conclusions: In working areas where asbestos-containing buildings are being demolished, including living environment surroundings, quickly and accurately monitoring airborne asbestos scattered in the air around the working area is highly important. For this, we believea mutual interface of existing PCM and a real-time monitoring equipment method is possible.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.24 no.4
• /
• pp.492-500
• /
• 2014

Objectives: The purpose of this study is to estimate the applicability of regional sample collection of environmental samples. The concentration of asbestos fibers were analyzed with two devices. One was an existing commercial air sampling pump that has been proved to be accurate and exact, and the other is a remodeled pump for sample collection which was made from an electric bubble generator originally designed for aquarium fish. Samples were collected with the two devices under the same environmental conditions and collection equipment. A comparative analysis of the concentration of ambient asbestos fiber was then performed. Methods: Based on previous research, six farmhouses with asbestos fiber slate roofs known to have high concentrations of asbestos fiber were selected. Using the existing commercial air sampling pump and the remodeled electric bubble generator, four to seven samples were collected each day one meter downwind from the edge of the slate roof at high volume (about 4 L/min) and low volume (about 1.4 L/min). The analyzer responsible for sample quality control of asbestos fibers counted the number of asbestos fibers with a phase microscope. Results: The rates of flow change of the existed sampler and the remodeled pump at high volume were 0.82% and 0.17%, respectively. The rates of flow change at low volume were 3.83% and 1.09%, but there was not significant difference. The rates of flow change are within the error range (${\pm}5%$) of OSHA analyzing methods. For the high volume sampler, the average asbestos fiber concentration in the air collected by the existed sampler is 6.270 fibers/L and for the remodeled one 5.527 fibers/L, not a significant difference. For the low volume sampler, the average asbestos fiber concentration in the air collected by the existed sampler is 7.755 fibers/L and for the remodeled one 7.706 fibers/L, not a significant difference. The total area of the slate roof of the targeted farmhouse has an effect on the concentration of asbestos fibers in the air from the existing pump and the remodeled one (p<0.01). Conclusions: The sampling function between the existing commercial pump and the remodeled one shows little difference. Therefore, the remodeled pump is considered a pump with a good availability for collecting ambient air asbestos samples.