The safest thing for people living within a few kilometres of the area would be to move away, if possible. And the time to return would be after it has rained in the area at least once. This would ensure that all the particles come down to the ground. As for those who cannot move, they can probably use an N-95 mask with a valve. So, when we were recommending N-95 for COVID, we were insisting on valveless masks, but for air pollution, we allow N-95 with valves, which allows you to exhale the air with less resistance, and when you inhale, you inhale through the masks. It is a one-way valve, and that would be the safest thing for people to use for at least a couple of days, particularly, if they are going outdoors in those localities.