EPA is only worried about dust particles which are in the size range of 0.5 to 5.0 micron. These particles are too small to be seen with the naked eye and are retained in the lung when breathed in. Larger particles get filtered out during inhalation by the mucous membranes in the nose and throat and smaller particles enter/exit the lungs with ease. The problem with visible dust is that microparticulate dust is probably floating around as well.

There also seems to be growing interest in aerosols which contain microbes lofted off of the surface of lagoons by wave action and dusts from animal waste in large animal feeding operations.

EPA is only worried about human exposure. Air conditioned cabs with a HEPA air filter solves a lot of the exposure problem.  Remember when only “sissy” farmers rode in cabs? Or filtered their air? 2 or 3 companies make positive pressure filtered air helmet systems for individual protection. Used by woodworkers with allergies to wood dust and farmers emptying out grain bins. Every other industry has learned how to deal with the dust issue and farming will be no different.

You may think that it is silly but you may want to ask you wife & kids.