Bill already said it, but it’s worth repeating. The cheapest and easiest method to minimize risk is to have good studio hygiene. It’s the old saw about an ounce of prevention being better than a pound of cure. If you generate minimal dust, or use wet cleanup methods frequently, you will cut airborne OHS risks drastically. Covering any glaze buckets in between dry glaze ingredient additions, mopping your floor after mixing glazes and any activity that gets clay on the floor and not sanding your work will drastically improve your air quality. For most clay purposes, cleaning and a good, well-fitting respirator for spraying/dusty activities are sufficient. An air cleaner is a nice-to-have.
As per the article Bill linked above however, an N100 filter is recommended for a respirator worn during glaze mixing, not N95. The best mask should be a well-sealed and properly fitted mask, and that will depend somewhat on the shape of your face. It’s better to try one on in person rather than just order online for that reason. It’s worth getting one with straps that distribute the weight evenly over your head for more comfort.
If you do shop for an air purifier, filter changes etc will vary by model and the volume of air it’s filtering. The particle size of concern with respirable silica is 10 microns or less. The particularly hazardous ones are the ones under 3 microns, so make sure your filter will actually grab those ones efficiently. Many are more concerned with allergens like pollen or pet dander, so they’ll pick up some >3micron particles, but how efficiently they do so and for how long is an important distinction.
There are so many articles available on this subject: OSHA, CDC, NIOSH, your public health and government sites. All can provide good guidance so you should read for your state for sure at a minimum. HEPA filtration is the only recognized filter that I know approved for effective removal especially in air filters and vacuums. Minimizing generation is super important so house keeping, wet not dry methods etc….. are most important.
Personal protective equipment such as N95 rated masks or other rated masks are also a common recommendation when sanding, glaze prep, etc…. I would start with google and your local health department. Avoiding generating dust is usually a very good first practice which consists of: don’t generate it indoors, so wet cleanup, hepa vacuum, etc… are common.
Some things you may see with clay and most clay studios
Vacuum your kiln after firing : use a real hepa rated vacuum.
Air filter: hepa rated
Mix glazes: do this outdoors with N95 mask or superior for personal protection or in an approved paint spray booth, or with approved exhaust.
Cleanup: wet cleanup only, no brooms or brushes etc…
Read through the documents, much has been written with most requirements unified under OSHA for employers / Employees in the US and uniform exposure standards through federal and state health standards. Your local health department should have plenty of information available right on their website.
All else fails, NIOSH has publicized suggestions as well for construction practices and personal filtration and protection. You may find them useful. Your source of silica are basically clays and glazes whereas construction activities pertain to cementitious mixing, grinding etc….. https://www.cdc.gov/niosh/docs/96-112/default.html#:~:text=Use vacuums with high-efficiency,being released in the air.. Your state health department likely has written materials that may be easier to read through, the NIOSH is just one of many.
It does not matter which source ……….. how to minimize, how to protect and how to collect are the relevant issues.
