The smaller a particle is, the deeper into the pulmonary system it penetrates. Respirable dust, the dust we inhale is made up of particles smaller than 5 thousandths of a millimeter (5 μm). Because the particles are so small, they can penetrate into the deepest parts of the pulmonary system where the air moves too slowly to be able to breathe them out again. The lungs’ way of protecting themselves is to wrap the foreign particles in nodules of connective tissue, which, in time, leads to pneumoconiosis or COPD (Chronic Obstructive Pulmonary Disease). Some types of particles, such as silica and asbestos dust, cannot be broken down by the body and are also sharp, which is why they continue to cause damage long after they have become lodged in the lungs.
The best protection is to remove dust at the source and never allow it to reach the air. Dust control has developed suction castings for most handheld and stationary machine, and also produces tailor-made suction castings.