During this past week, as we lived through heavy bouts of thick wildfire smoke in Northern Nevada, I watched people wearing masks choke on the odor. Their masking-up did them no good, physically.
Logic suggests that if they could smell the smoke, they were breathing in and choking on particulates. Now, the average size of a wildfire smoke particulate is about 0.3 microns.
Meanwhile, the larger Coronaviruses are around 0.2 microns, while most are less than 0.05 microns, smaller than the smoke particulate. So, it would appear that wearing a face mask is useless against both smoke particulates and the COVID-19 virus.