• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제23권4호
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• pp.393-401
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• 2013

Objectives: Endotoxins in dust generated in occupational settings is known to contribute to the occurrence of respiratory illness among workers. The relationship between the level of endotoxins in total dust or respirable particulates collected from swine farms and immunological markers related with respiratory allergy was evaluated among swine husbandry workers. Materials and Methods: Peripheral blood samples were collected from ten workers at ten swine farms at Gyeonggi province, Korea. Peripheral mononuclear cells were stimulated with phorbol 12-myristate 13-acetate and ionomycin for 48 hours. The levels of various cytokines produced at culture supernatants were determined using a commercially available ELISA kit. The concentration of particulate matter($PM_{10}$) in the indoor air of the swine farms was evaluated using a PVC membrane filter and mini volume air sampler, and endotoxin levels in the dust were measured by Limulus Amebocyte Lysate Kinetic QCL method. Results: Levels of endotoxins in the total dust were categorized into high(geometric mean: $109.35EU/m^3$) and low concentrations (geometric mean: $0.95EU/m^3$) for five swine farms. Interleukin-4 levels were higher in the high endotoxin group than in the low endotoxin group, while interferon-${\gamma}$ levels were lower in the high endotoxin group than in the low endotoxin group. The ratio (interferon-${\gamma}$ to interleukin-4), indicating immunologic skewedness against allergic reactivities, was lower in the high endotoxin group($1.15{\pm}0.60$) than the low endotoxin group($3.09{\pm}2.38$). In addition, the level of interleukin-13, another cytokine contributing to the occurrence of allergic responses, was significantly higher in the at the high endotoxin group($1.12{\pm}0.37ng/m{\ell}$) than in the low endotoxin group($0.37{\pm}0.04ng/m{\ell}$). Hematologic assessment showed significantly lower cellularity in the number of total leukocytes, neutrophils, and eosinophils in the high endotoxin group than in the low endotoxin group. Conclusions: Even though a sufficient number of swine workers and farms were not investigated, this study generlly suggests that the immunological function of swine farm workers exposed to high levels of endotoxin could be modulated toward allergic reactivities.

• Journal of Environmental Science International
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• 제25권10호
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• pp.1349-1368
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• 2016

Concentrations of fine particulate matter ($PM_{2.5}$) and several of its particle constituents measured outside homes in Houston, Texas, and Los Angeles, California, were characterized using multiple regression analysis with proximity to point and mobile sources and meteorological factors as the independent variables. $PM_{2.5}$ mass and the concentrations of organic carbon (OC), elemental carbon (EC), benzo-[a]-pyrene (BaP), perylene (Per), benzo-[g,h,i]-perylene (BghiP), and coronene (Cor) were examined. Negative associations of wind speed with concentrations demonstrated the effect of dilution by high wind speed. Atmospheric stability increase was associated with concentration increase. Petrochemical source proximity was included in the EC model in Houston. Area source proximity was not selected for any of the $PM_{2.5}$ constituents' regression models. When the median values of the meteorological factors were used and the proximity to sources varied, the air concentrations calculated using the models for the eleven $PM_{2.5}$ constituents outside the homes closest to influential highways were 1.5-15.8 fold higher than those outside homes furthest from the highway emission sources. When the median distance to the sources was used in the models, the concentrations of the $PM_{2.5}$ constituents varied 2 to 82 fold, as the meteorological conditions varied over the observed range. We found different relationships between the two urban areas, illustrating the unique nature of urban sources and suggesting that localized sources need to be evaluated carefully to understand their potential contributions to $PM_{2.5}$ mass and its particle constituents concentrations near residences, which influence baseline indoor air concentrations and personal exposures. The results of this study could assist in the appropriate design of monitoring networks for community-level sampling and help improve the accuracy of exposure models linking emission sources with estimated pollutant concentrations at the residential level.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제18권2호
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• pp.443-449
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• 2017

The imbalance of air supply and the exhaust on subway platforms has led to the installation of platform screen doors in underground subway stations. This imbalance causes the accumulation of pollutants on the platform and loss of comfort due to the lack of ventilation. In this study, a floor exhaust system was optimized using computational fluid dynamics (CFD) and an optimization program. The optimized floor exhaust system was manufactured and tested experimentally to evaluate the particle collection efficiency. CFX 17.0 and HEEDS were used to analyze the flow field and optimize the principal dimensions of the exhaust system. As a result of the three-step optimization, the optimized floor exhaust system had a total height of 1.78 m, pressure drop of 430 Pa, and particle collection capability of 61%. A fine dust particle collection experiment was conducted using a floor exhaust system that was manufactured at full scale based on the optimized design. The experiment indicated about 65% particle collection efficiency. Therefore, the optimized design can be applied to subway platforms to draw in exhaust air and remove particulate matter at the same time.

• Journal of Animal Environmental Science
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• 제16권2호
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• pp.99-108
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• 2010

The principal objective of this study was to investigate the cooling effects of geothermal heat pump system (GHPS) in farrowing house. A total of 96 sows were allocated to 2 pig housings (GHPS and conventional housing) with 48 for four weeks in summer season. During the experimental period of four weeks, the highest outside temperature observed was approximately $34.1^{\circ}C$, GHPS decrease indoor temperature of pig housing up to $30.9^{\circ}C$, but conventional pig housing was similar to outside temperature. Dust concentrations (maximum 61.4%) of particulate matter less than $10{\mu}m$ (PM 10) in GHPS-housing were lower than the conventional housing. GHPS showed no signigicant difference in carbon dioxide emission, whereas the ammonia gas concentration was significantly decreased in GHPS-housing compared to that of conventional housing. Sows in GHPS-housing showed significantly lower respiratory rate than those of the control group. GHPS did not affect hormone level, litter size and birth weight, but weaning weight of piglets was influenced by GHPS. Feed consumption of sows was significantly increased in GHPS-housing compared to the conventional hosing. These results suggest that GHPS decrease dust concentration, ammonia gas emission and indoor temperature of pig housing and may affect performance in sows and weaned piglets.