title: Airborne bacteria concentrations and related factors at university laboratories, hospital diagnostic laboratories and a biowaste site.
abstract: OBJECTIVE
  To evaluate concentrations of airborne bacteria in university laboratories, hospital diagnostic laboratories, and a biowaste site in Seoul, Korea. To measure total airborne bacteria (TAB), the authors assessed sampling site, type of ventilation system, weather and detection of Gram-negative bacteria (GNB), indoors and outdoors.
  
  
  METHODS
  An Andersen one-stage sampler (Quick Take 30; SKC Inc) was used to sample air at a flow rate of 28.3 l/min for 5 min on nutrient medium in Petri dishes located on the impactor. A total of 236 samples (TAB, 109 indoor and nine outdoor; GNB, 109 indoor and nine outdoor) were collected three times in each spot from the 11 facilities to compare airborne bacteria concentrations.
  
  
  RESULTS
  TAB concentrations ranged from undetectable to 3451 CFU/m³ (mean 384 CFU/m³), and GNB concentrations from undetectable to 394 CFU/m³ (mean 17 CFU/m³). TAB concentrations were high in window-ventilated facilities and facilities in which GNB were detected; concentrations were also high when it was rainy (all p values <0.05). TAB concentrations correlated significantly with GNB (r=0.548, p<0.01), number of bacteria species (r=0.351, p<0.01) and temperature (r=0.297, p<0.01). The presence of heating, ventilating, and air conditioning (HVAC), the number of TAB species and the detection of GNB affect TAB concentrations in laboratories.
  
  
  CONCLUSIONS
  It is recommended that special attention be given to regular control of indoor environments to improve the air quality of university and hospital laboratories.
authors.affiliation: Institute of Health and Environment, School of Public Health, Seoul National University, Seoul, South Korea.
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Hwang
authors.forename: Dong Uk
authors.initials: DU
authors.lastname: Park
authors.forename: Kwon Chul
authors.initials: KC
authors.lastname: Ha
authors.forename: Hyun Woo
authors.initials: HW
authors.lastname: Cho
authors.forename: Chung Sik
authors.initials: CS
authors.lastname: Yoon
mesh_terms: D000391:Air Microbiology; D016902:Air Pollution, Indoor / Q000032:analysis; D001419:Bacteria / Q000145:classification / Q000302:isolation & purification*; D004784:Environmental Monitoring / Q000379:methods; D006090:Gram-Negative Bacteria / Q000145:classification / Q000302:isolation & purification; D006801:Humans; D006813:Humidity; D007753:Laboratories / Q000592:standards / Q000706:statistics & numerical data*; D007755:Laboratories, Hospital / Q000592:standards / Q000706:statistics & numerical data; D017744:Medical Waste Disposal / Q000592:standards / Q000706:statistics & numerical data; D016273:Occupational Exposure / Q000032:analysis*; D056910:Republic of Korea; D014691:Ventilation
chemical_list: D017744:Medical Waste Disposal