title: Large particles are responsible for elevated bacterial marker levels in school air upon occupation.
abstract: Muramic acid (Mur) is found in bacterial peptidoglycan (PG) whereas 3-hydroxy fatty acids (3-OH FAs) are found in Gram-negative bacterial lipopolysaccharide (LPS). Thus Mur and 3-OH FAs serve as markers to assess bacterial levels in indoor air. An initial survey, in a school, demonstrated that the levels of dust, PG and LPS (pmol m(-3)) were each much higher in occupied rooms than in the same rooms when unoccupied. In each instance, the Mur content of dust was increased and the hydroxy fatty acid distribution changed similarly suggesting an alteration in the bacterial population. Here, findings are compared with results from two additional schools. Follow-up aerosol monitoring by particle size was also performed for the first time for all 3 schools. The particle size distribution was shown to be quite different in occupied versus unoccupied schoolrooms. Within individual classrooms, concentrations of airborne particles [greater-than-or-equal]0.8 [micro sign]m in diameter, and CO(2) were correlated. This suggests that the increased levels of larger particles are responsible for elevation of bacterial markers during occupation. Release of culturable and non-culturable bacteria or bacterial aggregates from children (e.g. from flaking skin) might explain this phenomenon.
authors.affiliation: Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Alvin
authors.initials: A
authors.lastname: Fox
authors.forename: William
authors.initials: W
authors.lastname: Harley
authors.forename: Charles
authors.initials: C
authors.lastname: Feigley
authors.forename: Deborah
authors.initials: D
authors.lastname: Salzberg
authors.forename: Charlotte
authors.initials: C
authors.lastname: Toole
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Sebastian
authors.forename: Lennart
authors.initials: L
authors.lastname: Larsson
mesh_terms: D000336:Aerosols / Q000032:analysis; D016902:Air Pollution, Indoor / Q000032:analysis*; D001419:Bacteria; D015415:Biomarkers / Q000032:analysis*; D002245:Carbon Dioxide / Q000032:analysis; D004391:Dust; D004784:Environmental Monitoring / Q000592:standards; D010316:Particle Size; D015203:Reproducibility of Results; D012574:Schools
chemical_list: D000336:Aerosols; D015415:Biomarkers; D004391:Dust; D002245:Carbon Dioxide