Assessment of Airborne Bacteria and Fungi in Various University Indoor Environments: A Case Study in Chang'an University, China

Abstract

To quantify characteristics of bioaerosols in university indoor environments, concentration and size distribution of airborne culturable bacteria and fungi were examined in four types of buildings of Chang'an University in Xi'an, China, from March, 2012 to February, 2013. Indoor temperature and relative humidity (RH) were also measured to determine correlations between bioaerosols and environmental parameters. Results showed that concentration and size distribution of airborne bacteria and fungi varied in various indoor environments due to the appearance of different indoor sources and human occupancy. The highest mean concentrations of airborne bacteria and fungi were found in the canteen (1,025±91 and 699±57 CFU/m3), followed by the clinic and dormitories, and the lowest in classrooms (479±66 and 345±15 CFU/m3). Airborne bacteria and fungi here showed higher concentrations than those of western universities. Similar seasonal variations of airborne fungal concentrations were observed for all indoor environments, with higher levels in fall and winter and lower in spring and summer. Indoor temperature showed more significant correlation with bioaerosols than RH in all indoor environments. Another important finding was that more than 75% bacterial and fungal aerosols were in respirable size range in each indoor environment.