Is it okay to wear a mask when running?

This is terrible. In a day, the air quality is the worst in the morning and evening. I don't know where you are. If you are in an industrial area or where there are many cars, the air quality will be worse. Four or five in the afternoon is the best time to exercise and increase muscle strength. You're going to run away with a mask. Although you can avoid inhaling too much particulate pollutants, running with a mask will affect your breathing and lung function. You exercise for yourself.