Assessment of types of bacterial bio-aerosols and concentrations in the indoor air of gyms.

The presence of airborne microorganisms in indoor air (home and work) is a serious public health concern. Bio-aerosols have a significant role in indoor air pollution as they can be pathogenic or cause an allergic reaction following inhalation, ingestion or skin absorption. This study aimed to assess bacterial bio-aerosols in the indoor air concentration of gyms, and its relationship with gym area per person, temperature, and relative humidity. Sampling was performed by the National Institute for Occupational Safety and Health (NIOSH) method 0800-0999 and using an Anderson single-step sampler. Fifty-five gyms were selected with simple random sampling method and 165 samples collected for evaluation of bacterial bio-aerosols. The concentrations of airborne bacteria were measured as colony-forming units per cubic meter of air (CFU/m3) collected by impaction on to tryptic soy agar plates. The maximum and minimum densities of bacteria in the air of gyms were 877 and 117 CFU/m3, respectively. Pseudomonas, Staphylococcus and Escherichia Coli had an order of the highest to lowest frequency among the microorganisms, respectively. Generally, with increasing temperature and humidity, the density of bacteria was increased. The higher amount of the microorganisms was observed in the air of gyms in the lower available area per person. Athletes are at risk of high exposure to the bacterial bio-aerosol that can affect their health.