Wood dust of any kind, even if it doesn't cause a specific allergic or toxic reaction is a threat.
What is your tillering method? Does it involve a lot of grinding, power sanding? Do you only sand after tillering? In general using edged tools, spokeshaves and scrapers produces far less dust. Rasps are good too.
If you work in a confined area, ie a workshop it increases your exposure. Even when you aren't sanding, there are still particles floating in the air, so you would need to wear a mask all the time, unless you use a workshop air filtration device religiously. Any power tools or machines should be hooked up to a dust extractor.
Working outdoors, when grinding or sanding(always with a mask) goes a long way in reducing problems.
I developed severe sinus, post nasal drip, which led to almost being hospitalised due to fluid build up on the lungs. I also had constant headache due to sinus pain. I was using a mask at the time but it was only a basic level nuisance mask.
I used an asthma puffer to help de constrict my airways. Changed to a P2 rated mask, or used a Trend headshield filter. One of the key factors in getting rid of the chronic irritation, was using a nasal rinse bottle, which uses a mild saline solution to flush out the sinuses and nasal cavity.
Hope this helps.
