Dust is the bane of the woodturner and woodworker. We tend to think that it exists only during sanding. Whereas we create the most dust while sanding, dangerous particles can be created any time we take a tool to wood (or corian, acrylic, etc). We stir up dust in our shops with every step we take and tool that we pick up. I used to be one who (falsely) believed that things were okay so long as my air filter was running and I wasn’t sanding. Since my shop isn’t always (meaning ever) truly clean, I would be stirring up the tiny dust that is so very dangerous to our health. This is dust that you and I can’t even see!
A micron is one millionth of a meter. The human eye can see something as small as 40 microns — possibly as small as 10 microns, but us woodturners aren’t known for our youthful, 20-20 vision! For comparison, a human hair is in the range of 70 microns in diameter. When we create dust, about 5% of it is considered airborne dust — dust light enough to not fall directly to the ground, which has the highest chance of inhalation. About a third of that is ‘fine’ dust, which is light enough to stay in the air indefinitely due to normal air currents within a house or workshop. THAT is the dust that pretty much only stops when it hits lung tissue! Some of these particles are measured in the tenths of a micron range.
Over time, these small particles can cause enormous amounts of health problems. Some woods are irritants, some toxic, some carcinogens, and some are sensitizers. Whereas a sensitizer may not cause any initial problems, recurring exposures may cause heightened effects. As for filter sizes, the finer the better! This goes for air filter systems or masks. 0.2 microns for masks is a great goal to set, but don’t let that stop you from wearing something if you can’t find one that filters that small. Besides the normal allergic reactions, inhaling fine particles can cause long-term damage. Do what you can to prevent it from happening to you!
One of the finest resources on the dangers of dust as well as how to approach a solution towards a dust-free environment to work on is Bill Pentz’s website. He goes into more detail than most people can ever hope to absorb. He became an expert after hospitalization due to dust-related health issues. If you want more info on dealing with dust, his is the site to visit. The Wood Database site keeps a wood allergies and toxicities chart on several species of wood that is useful as well. It may help you to determine which woods you should shy away from turning.