Characteristics of biological and non-biological aerosol particles in indoor environment and their inhalable fractions in the human lung

Air quality of public buildings is an important to assess human health. School and university buildings represent an important category of indoor environments. This study aimed to evaluate the concentration and size distribution of fungal and non-biological aerosol particles in classrooms of Minia university, Egypt. In addition, the inhalable fractions were determined and indoor exposure dose (IED) of fungi and aerosols were estimated for the students. A six-stage Andersen impactor was used for collecting the fungal particles and Berner cascade impactor was used for sampling the non-biological aerosol particles. indoor average concentration of fungi was 307±102 CFU/m3. The most frequently isolated genera were Aspergillus niger with concentration 175±85 CFU/m3 representing about 57% of the of the total collected fungi. Aspergillus flavus represents about 31% of the total fungi with concentration 96±32 CFU/m3. Low concentration 36 ±12 CFU/m3 of Penecillium was investigated representing only 12% of the total collected fungi. Mean concentration of non-biological aerosols was 442±99 µg/m3. The concentration of airborne fungal aerosol particles were lower than the World Health Organization guide line While the corresponding concentration of non-biological aerosols exceeds WHO limit. Most of the collected fungal particles were found in the inhalable size range (< 5µm) where inhalable fraction of fungi represents 84% of the total collected particles while inhalable fraction of non- biological aerosols represents 92% of the total collected particles. Size distributions of biological and non-biological aerosols were bimodal in nature. IED of fungi was 25.6 CFU/kg While the IED of non-biological aerosols was 37 CFU/kg.