The comfort parameters in indoor air of sports facilities with different ventilation regimes

Introduction: In Portugal, during COVID19 pandemic, sport and fitness facilities were closed. When lockdown has been lifted, in order to prevent the spread of infection, indoor sport facilities were subject to specific regulations that limited indoor occupancy as well as manner of air ventilation. This study aims to analyze the impacts of these ventilation restrictions on indoor air comfort parameters in sport fitness facilities. Methodology: Temperature (T; ºC), relative humidity (RH; %), and carbon dioxide (CO2) were continuously monitored (41 days; spring and autumn) in four fitness centers situated in Oporto metropolitan area: two of them under normal ventilation conditions (i.e. before lockdown; NV1 and NV2) and two of them under temporary restrictions for indoor ventilations and occupancy (RV1 and RV2). Results and Discussion: Under normal ventilation conditions, T in fitness centers slightly varied (in NV1:22-25 ºC; NV2: 20-23 ºC) but in both clubs the comfort recommendations (18-25 ºC) were fulfilled. On contrary, RH were below guideline values (55-75%) in NV1 (47-54%) whereas at NV2 (66-73%) it fulfilled the recommendations. When specific health regulations took place, mean T ranges were similar in both clubs (RV1: 21-23 ºC; RV2:21-23 ºC) but they both exceeded recommended comfort levels (16-21 ºC). Mean RH were in accordance with the legislative values, but the very high temporal maxima (up to 75 and 89%) indicate the possible discomforts the that exercisers might have experienced. Concerning the CO2, the obtained results showed that indoor levels decreased when specific health restrictions were in force (11-121%) most likely due imposed guidelines for human occupancy. Conclusions: The restrictions for ventilation and human occupancy positively impacted indoor levels of CO2. However, T and RH were on several occasions outside the recommended comfort levels, especially during group activity classes. As regular exercising in environmental conditions, such as elevated T and increased RH can cause health discomforts, these parameters should be carefully maintained within the recommended ranges even under restricted ventilation scenarios.