O3 concentration and duration of exposure are factors influencing the environmental health risk of exercising in Rio Grande, Brazil.

Ozone (O3) represents a great threat to human health, contributing to respiratory diseases and premature mortality. This pollutant is often considered a critical pollutant in regions of southern Brazil. Exposure to this pollutant during vigorous physical activity should be the subject of thorough investigations due to the increased ventilation rate and altered breathing pattern present during vigorous physical activity that result in greater inhalation of O3. Thus, this study aimed to evaluate the health risk of exposure to low, mean, and high concentrations of O3 during different durations of exercise in the city of Rio Grande (southern Brazil). Healthy young men (n = 45) performed cardiopulmonary exercise testing, and ventilation rate data were collected to predict total ventilation and pollutant inhalation during a 5 km running session. The O3 concentration in the city of Rio Grande was obtained from data reported by the Copernicus Atmosphere Monitoring Service (CAMS). The environmental health risk was calculated based on the potential intake dose. The lowest, mean, and highest concentrations of O3 detected during the monitoring period were 32.5, 64.9, and 115.2 µg/m3, respectively. In all evaluated scenarios, there was a toxicological risk (RQ > 1), except when exercising when the O3 concentration was lowest for the shortest length of time (p < 0.001). As the concentration of O3 and the duration of the exposure increase, the health risk is increased. Therefore, O3 concentration and duration of exposure are factors influencing the health risk of exercising. These findings are extremely relevant in cities that have high levels of O3, such as the city of Rio Grande.