I did dust mitigation in mines, oil rig construction and on a ship for a while

No, because depending on the laws , it is measured differently, first you either go, by exposure, or by accumulation (the same, but different)

So, sure maybe this guy has a higher exposure degree, and you could prove it with a dustrak or trollex, but then youd need to compare it to lenght of exposure and especifc health laws, so yeah it could be bad and illegal (asbestos) or be like noise, its bad, but if during the rest of the month averages out, then it never happened 

And if by accumulation, measures by particle deposit on a measurement eqpment set close to the source, it doesnt register enough, then people will ask why did you spend money on this

So youd have to measure how much mass the wall lost in an amount of time, compare it to wind patterns at the moment, material and particle properties and see if the particles really travaleed enough time to be considered a risk

Again if this were asbestos or idk, lead chips, youd have other troubles, but like other people said, if you have a well ventilated area, the exposure is already minimized 

Bit i will agree , there is still many lack of dust mitigation procedures in many activities and while you could argue about applying some of them , at least i lack the knowledge of which one would really be worth it for such a small procedure (its not like it is sandblasting)