Here’s a heads-up to those who are sensitive or allergic to dust, or suffer from respiratory illnesses: try to avoid getting a job at a grain mill.
Why? Because grain mills, elevators, and other similar processing plants are rich sources of point-source air pollution. Although somewhat dated, this journal article by Mclouth and Paulus (1961) gives a succinct overview of the types of air pollution that may be present in grain mills and elevators.