Investigation and Disinfection of Environmental Microbes in Sports Fitness Center

Abstract The COVID-19 pandemic shows that indoor air disinfection is extremely important. As early as 2012, Taiwan has released indoor air quality standards, and in 2017 announced the second batch of places that should meet indoor air quality standards including sports and fitness places. In this study, the indoor air quality was monitored in the indoor exercise and fitness center under normal operating conditions of air conditioning and ventilation as well as user flow. Chlorine dioxide and weak acid hypochlorite solutions, and water scrubbing were used to improve the quality of the indoor environment under different operating modes. This study investigated the air quality improvement in terms of bacteria and fungi contamination of the indoor exercise and fitness center under normal operating conditions including air conditioning, ventilation, and user flow. In addition, bacteria contamination and disinfection on sports equipment surface were also examined. Background bacteria and fungi densities in bioaerosols were in the range of 249 ± 65 to 812 ± 111 CFU/m3 and 226 ± 39 to 837 ± 838 CFU/m3 in the indoor air of the fitness center and 370 ± 86 to 953 ± 136 CFU/m3 and 465 ± 108 to 1,734 ± 580 CFU/m3 in the outdoor air, respectively. Chlorine dioxide and weak acid hypochlorous water aerosols could remove both bacteria and fungi much better than water scrubbing. Contact time of 15 minutes was sufficient to control both bacteria and fungi to comply with the official air quality standards. User density and carbon dioxide deteriorated both bacteria and fungi disinfection performance whereas temperature was only statistically significant on fungi disinfection. Other factors including relative humidity, airflow velocity, and particulate matters did not have any statistically significant effect on microbial inactivation. Handle of bicycle, dumbbell, and sit-up bench were found to be contaminated with bacteria and E. coli. Detected densities for bacteria and E. coli on the surface of these sport equipment were in the range of 390 ± 2 to 3,720 ± 736 CFU/cm2 and 550 ± 70 to 1,080 ± 114 CFU/cm2, respectively. Microbial densities detected largely depended on the number of users for each specific equipment. Chlorine dioxide and zinc oxide were noticeably better than weak acid hypochlorous water and commercial disinfectant in term of bacteria inactivation whereas all tested disinfectants had comparable effectiveness on E. coli disinfection. Targeted microorganisms were sufficiently inactivated within 2 minutes after the application of disinfectant.