Characterization, identification and comparison of indoor microbial fungi and bacteria between urban and suburban schools in Penang, Malaysia

Abstract

School environment plays a big role in influencing a child’s health and well being. This is due to the known fact that children commonly spend a long duration of time in school. Children’s growing lungs present a large surface area that enables pollutants to be easily absorbed. Therefore, environmental condition in school is one of the main. Since studies on indoor microbial fungi and bacteria is limited, this preliminary study was aimed to determine the concentration of fungi and bacteria in the indoor air in selected locations in the schools and to compare them between the urban and suburban schools. Duo SAS Super 360 Microbiological Air Sampler was used to collect air samples from 8 urban and 2 suburban schools in Penang. Temperature, relative humidity and carbon dioxide level were measured using TSI Q-TRAK Plus IAQ Monitor Model 8554. Fungi and bacteria were identified using Lactophenol Blue staining for fungi and Polymerase Chain Reaction (PCR) for bacteria. Eight locations in each school were selected as sampling points. All eight urban schools exceeded the permitted limit of microbial fungi concentration recommended by ACGIH. Aspergillus has the highest occurrence range (75-100%) followed by Penicillium (37-75%) and Rhizopus (0-75%). Highest occurrence range of microbial bacteria was Staphylococcus Sp. (62-100%), Bacillus sp. (50-100%) and Corynebacterium sp. (37-88%). Microbial fungi concentrations were highest in sports equipment room in 6 urban schools and lowest in canteen in all 8 urban schools. However, microbial bacteria concentration was high in both classrooms and sports room but lowest in the canteen. There was significant difference between fungal concentration in urban and suburban schools (p < 0.05). A significant positive correlation was observed between fungal concentration and carbon dioxide (p < 0.05) in classrooms. In conclusion, carbon dioxide influences the concentratio