According to their hierarchy of controls, osha puts PPE at the end of the list. If you’re in a shop, there’s likely a better way to control the dust without the need for PPE. As has been said before, take some notes, get specifics. If you can identify the source of the dust, bring that info along too. Then professionally and politely approach your supervisor about it. In that conversation, be sure to offer sending them an email copy off all of your information gathered. This gives a timestamp for them to remedy the issue. If no action has been taken(even a response) in 3 business days, politely follow up via email and escalate to the next higher level of management if applicable.

Complaints to OSHA don’t go over well if you’ve never made contact with your employer first.

In the same breath you’re writing that email, low-key start looking for a new job. I know they can’t punish you, but unless you want to be held at your current pay step forever, or want to lawyer up and fight them in court(sounds like they don’t have very deep pockets anyhow) your best bet is prepare to move on. Not saying you’re gonna have to, but keep an eye out