Q: I keep seeing people out mowing and doing yard work wearing face masks, even in very hot weather. Is this necessary, or even advisable?
A: If they are like me, they may be wearing a mask to keep out allergens and particulates from doing yard work.
Long before COVID-19, people were wearing masks when doing yard work. There would be no reason for them to be wearing them to protect others from COVID-19, assuming that they are doing the yard work alone or with household members.