Just be careful of spraying anything containing SiO2 at a fine enough particle size to use for finishes... Google silicosis. And if the particles are small enough, they can pass through the lungs and make it to the bloodstream.
We're in the early days of using nanoparticle tech. There are likely to be many problems that surface over the years as we get it figured out. There wasn't and may not be much regulation about it. It is a newish area of risk.
Not all that many years back there was at least one brand of popular shampoo that used nano plastic in the formulation. It worked very well as a shampoo, and added a little extra sheen to the hair. A little while later the problems with nano plastics started to be known, and that formulation was quietly dropped.
Lots of people and industries are still likely thinking of only chemical based risk (or what isn't regulated as a risk so they can get away with it) and not necessarily thinking that particle morphology can also cause unique risks to individuals or the environment.
Asbestos, for instance, isn't dangerous because of its chemical composition. It's dangerous because of its particle morphology. Ditto cotton, which many don't realize. Or to some extent the Aramid family of fibers. We've learned over the years that micro fibers can cause problems for the lungs if they are capable of hooking on or going deep enough they can't be brought back up with mucus.
mesothelioma.
Coal dust - black lung.
Cotton dust - brown lung.
Silicosis.
etc.
Unfortunately there is likely to be a long list of etc added over the coming years. Many industries take the approach that if it is not known to be unsafe (or in some cases, regulated) then it is ok to do it. So take care with any aerosol microparticle or particularly nanoparticle mix. Your HEPA filters might not be much good for the latter. And the resulting dust is going somewhere. It can be stirred back up when you are not wearing your filters.
I'm not trying to be alarming. Just realize that your safety is not necessarily the primary concern of the manufacturer of every product you might encounter. And they may not know. Your safety is up to you.
In testing for the safety of something, IIRC the gold standard was 7 generations of exposure and see what happens to the population. Most everything we are exposed to that humans make wasn't around 7 generations ago. We're just getting started with this experiment!
Most of the testing we have relates to what happens to short term or sudden exposure. LD50 values for instance. And unfortunately MSDS which used to be useful got lawyered over and now no longer provide much useful info in most cases. For those who don't know, at least in the US, an MSDS is required to be available for any manufactured chemical product.
Feel free to correct any misstatements I made!
Gerald