Particulate Siloxane and Cigarette Smoke Organic Aerosol in a Gym

Understanding the composition and concentration of pollutants in the gym environment is crucial for evaluating the potential health risks associated with physical exercise. Here submicron aerosol composition in a basement gym was characterized by a high-resolution aerosol mass spectrometer. Our results showed higher fraction of organic aerosol (OA) in particulate matter indoors (50%) than outdoors (40%). Positive matrix factorization identified two distinct gym-related OA factors, i.e., siloxane OA (SiOA) and cigarette smoke OA (CSOA). Unexpectedly high concentrations of particulate siloxane, up to 6 μg m^–3 and contributing 7–11% of OA were observed, and the variations of SiOA were strongly correlated with carbon dioxide emissions from human activities. The source of SiOA is likely from the lubricant of silicone polymers used in fitness equipment during exercise. Additionally, the presence of CSOA in the gym, on average contributing 6–7% of OA, is primarily linked to outdoor transport during ventilation. Our results highlight the significance of thorough investigations of air quality across different gyms with varying equipment, human occupancy, and ventilation conditions which is pivotal for implementing effective measures that ensure healthy indoor air quality and minimize potential health risks associated with exercise in gyms.