I come from a time when air filters and dust systems were a vanity item, and real men didn't use them. There's a long list of hazardous, toxic, and just plain dangerous media connected with woodworking and finishing.
First off, if you can smell it, it's dangerous. Now, that sounds too simplistic doesn't it. If you can smell it, it's in the air, and it can enter our body by direct skin contact, inhalation, basically any orifice is an opening (eyes, ears, nose, mouth). Chemicals are difficult, as even with a respirator, our skin is still at risk.
Wood dust, just cannot be processed enough by our body without some deleterious effect. Most woodworkers take off their masks way too soon anyway. Those paper masks with the bendable nose piece are absolute junk. If you saved at the end of the day what you blow out of your nose, you may have enough to save to make some particleboard.
I will say my exposure is much higher than a weekend warrior. Working 6 sometimes 7 days a week, likely puts me in the top percentile for high susceptibility. It was only the last 25 years that I installed a DC that was effective. Even with that, the ambient dust is incredible.
So, what can I attest to...
I have tendonitis in the hands and fingers
I have nerve damage in the hands and fingers.
I have a breathing disability.
I am a cancer of the bladder survivor.
I have other problems, but those are the crux of the problems from chemical and dust exposure. If I had to do it over, I would have been born rich. If that didn't happen, I would have used as much of the safety and protective gear that is available. IMO, anything else is self destructive, and just plain foolish.