title: Seasonal variation in airborne endotoxin levels in indoor environments with different micro-environmental factors in Seoul, South Korea.
abstract: This study evaluated the variation over a year in airborne endotoxin levels in the indoor environment of five university laboratories in Seoul, South Korea, and examined the micro-environmental factors that influenced endotoxin levels. These included temperature, relative humidity, CO2, CO, illumination, and wind velocity. A total of 174 air samples were collected and analyzed using the kinetic limulus amebocyte lysate assay. Endotoxin levels ranged from <0.001 to 8.90EU/m(3), with an overall geometric mean of 0.240EU/m(3). Endotoxin levels showed significantly negative correlation with temperature (r=-0.529, p<0.001), CO2 (r=-0.213, p<0.001) and illumination (r=-0.538, p<0.001). Endotoxin levels tended to be higher in winter. Endotoxin levels in laboratories with rabbits were significantly higher than those of laboratories with mice. Multivariate regression analysis showed that the environmental factors affecting endotoxin levels were temperature (coefficient=-0.388, p<0.001) and illumination (coefficient=-0.370, p<0.001). Strategies aimed at reducing airborne endotoxin levels in the indoor environments may be most effective if they focus on illumination.
authors.affiliation: National Cancer Control Institute, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Gyeonggi-do, South Korea.
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Hwang
authors.affiliation: Occupational Safety and Health Research, Ulsan, South Korea.
authors.forename: Dong Jin
authors.initials: DJ
authors.lastname: Park
authors.affiliation: Institute of Environmental and Industrial Medicine, Hanyang University, Seoul, South Korea.
authors.forename: Wha Me
authors.initials: WM
authors.lastname: Park
authors.affiliation: Department of Environmental Health, Korea National Open University, Seoul, South Korea.
authors.forename: Dong Uk
authors.initials: DU
authors.lastname: Park
authors.affiliation: Research Institute of Standards for Environmental Testing, Seoul, South Korea.
authors.forename: Jae Kyoung
authors.initials: JK
authors.lastname: Ahn
authors.affiliation: Institute of Health and Environment, School of Public Health, Seoul National University, Gwanak ,1 Gwanak-ro, Seoul, South Korea. Electronic address: csyoon@snu.ac.kr.
authors.forename: Chung Sik
authors.initials: CS
authors.lastname: Yoon
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D004731:Endotoxins / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D005160:Facility Design and Construction / Q000379:methods / Q000592:standards*; D008029:Lighting; D012621:Seasons; D066106:Seoul; D013696:Temperature
chemical_list: D000393:Air Pollutants; D004731:Endotoxins
keywords: Animal laboratory; Endotoxin; Illumination; Microbial laboratory; Seasonal variation; Temperature