As someone who has worked in an industrial environment, and who has had to wear respirators and other PPE, I can say that N95 respirators do not need to be 'professionally fitted'. They do need to fit just right, but the users themselves can do that. Yes, they can be uncomfortable if you've never worn a mask before, but once you are used to them you can wear them all day (as many many workers do everyday).
While the author focusses on fitting, he completely ignores the other issue with N95 masks: there are many different types that are designed to filter different things. There are different masks for dusts and particles, nuisance odours, welding fumes, acid gasses, organic vapors and biologicals. The author ignores that people will need to know what type of respirator they need as buying the wrong type will make it far less effective. Not all N95 respirators are the same. For a sutiation like this, a dust and particle filter with nuisance level acid gas (NOx, SO2, etc) would be better, but unlikely to be found at many hardware stores.
What people don't seem to realise is that the gasses that make up smog (CO, NOx, SO2, ozone, organic compounds) can be just as damaging, if not more, than the dust and particulates. Even N95 masks only filter out nuisance levels of these.