title: Quantitative assessment of bio-aerosols contamination in indoor air of University dormitory rooms.
abstract: OBJECTIVE
  The purpose of this study is to provide insight into how students are exposed to indoor bio-aerosols in the dormitory rooms and to figure out the major possible factors that govern the contamination levels.
  
  
  METHODS
  The Bio-aerosols concentration level of indoor air of thirty dormitory rooms of Jimma University was determined by taking 120 samples. Passive air sampling technique; the settle plate method using open Petri-dishes containing different culture media was employed to collect sample twice daily.
  
  
  RESULTS
  The range of bio-aerosols contamination detected in the dormitory rooms was 511-9960 CFU/m(3) for bacterial and 531-6568 CFU/m(3) for fungi. Based on the criteria stated by WHO expert group, from the total 120 samples 95 of the samples were above the recommended level. The statistical analysis showed that, occupancy were significantly affected the concentrations of bacteria that were measured in all dormitory rooms at 6:00 am sampling time (p-value=0.000) and also the concentrations of bacteria that were measured in all dormitory rooms were significantly different to each other (p-value=0.013) as of their significance difference in occupancy (p-value=0.000). Moreover, there were a significant different on the contamination level of bacteria at 6:00 am and 7:00 pm sampling time (p=0.015), whereas there is no significant difference for fungi contamination level for two sampling times (p= 0.674).
  
  
  CONCLUSIONS
  There is excessive bio-aerosols contaminant in indoor air of dormitory rooms of Jimma University and human occupancy produces a marked concentration increase of bacterial contamination levels and most fungi species present into the rooms air of Jimma University dormitory were not human-borne.
authors.affiliation: Department of Environmental Health Science and Technology, College of Public Health and Medical Science, Jimma University, Ethiopia.
authors.forename: Samuel Fekadu
authors.initials: SF
authors.lastname: Hayleeyesus
authors.affiliation: Department of Environmental Health Science and Technology, College of Public Health and Medical Science, Jimma University, Ethiopia.
authors.forename: Amanuel
authors.initials: A
authors.lastname: Ejeso
authors.affiliation: Department of Dentistry, College of Public Health and Medical Science, Jimma University, Ethiopia.
authors.forename: Fikirte Aklilu
authors.initials: FA
authors.lastname: Derseh
keywords: bacteria; bio-aerosol; dormitory room; fungi; indoor air; sedimentation technique