The Continuous Monitoring of Indoor Airborne Endotoxins in a Campus Environment

摘要

Campus is a small community, with representative infrastructure and public spaces, not only has the general characteristics of indoor environment that large varities of pollutants, wild source, long contacting time andlong-term accumulation, but also has relatively dense personnel, leading monitoring and analysis to more complex and difficult. The impact of environmental pollution on the campus student health has become a problem can not be ignored.Endotoxins, which comprise a complex of lipopolysaccharides (LPSs) and proteins, are widely distributed in the outer membrane of the cell wall of Gram-negative bacteria and other microorganisms, such as chlamydia, rickettsia, and spirochetes. Chronic exposure to endotoxins can induce and exacerbate airway symptoms, leading to asthma, cough, and impairment of lung function, including chronic obstructive pulmonary diseaseand organic dust lung diseases.From 26 April to 10 May 2015, we collected air samples using AGI-30 impingers for the quantification of indoor airborne endotoxin, bioaerosol, fine PM (PM_(2.5)) and also TVOC in Tianjin University. The geometric means for endotoxin, bioaerosol, PM_(2.5)and TVOC concentration were 491.67 EU/m~3 (range: 147.6-592.08), 50.42 CFU/m~3 (range: 7-158), 594.63ppm (range: 81.5-1147) and 43.04 (range 1.88-207) respectively. Through monitoring the space-time distribution of endotoxin in eight main campus spots (dormitories, laboratories, classrooms, cafeteria, school hospital, offices, gym and swimming pool), we came to the conclusion that the main factors affecting the distribution are the source of microorganisms and the cumulative effect of endotoxins. By comparing the different trends between endotoxins and other indicators, we found that there is no obvious relationship between endotoxins and bioaerosols, fine PM or TVOC neither. Meanwhile, the change of endotoxins concentration is relatively flat within a day.The results of our research providedthe first continuous time series of airborne endotoxin concentrations in Tianjin, and identifies its potential associations with atmospheric factors, providing a reference for researchers studying on indoor toxic substances and health effects, which can help control and improve the indoor environment quality.