Obesity and physical inactivity threaten human health, and both could be solved with exercise. However, a higher amount of pollutants is inhaled during exercise. Exposure to air pollution increases the incidence and progression of diseases. Therefore, the aim of the study was to investigate the rate of pollution inhalation of lean, overweight, and obese individuals in a low and high-intensity hypothetical exercise session. Healthy sedentary men (n = 135) classified as lean, overweight, or obese were enrolled in our study. All participants performed a cardiopulmonary exercise testing (CPX) to collect ventilation rate (VE) data, which was used to predict total ventilation and pollutant inhalation of a 5-km running session. Air pollutant concentration of Sao Paulo City, Brazil was evaluated and the toxicological risk was estimated based on the potential intake dose. The concentrations of PM(2.5)were 29.57 mu g/m(3)and 51.71 mu g/m(3), PM(10)were 45.85 mu g/m(3)and 74 mu g/m(3), NO(2)were 63.71 mu g/m(3)and 66.65 mu g/m(3), and O(3)were 69 mu g/m(3)and 37 mu g/m(3), respectively in the summer and winter. In the hypothetical exercise session, total VE and time in both the first and second threshold were increased in the obese group (p < 0.001) (p < 0.001). The inhalation of PM2.5, PM10, NO2, and O-3, during the hypothetical session, was increased in obese individuals (p < 0.001). Obese individuals should be considered a susceptible population, once they are more exposed to air pollution during exercise.