Dust is defined as a fine suspension of solid particles in the air. The causes for the presence of dust may be mechanical splitting (cutting), chemical reactions, condensation processes or the swirling up of solid substances. When dust suspended in the air is inhaled, human health may be impaired (silicosis may develop), and high concentrations give rise to the risk of fire or explosion. Dusts are regarded as work substances, i.e. wood dust in a cabinet makers’ workshop or flour dust in a bakery are classified as hazardous substances within the meaning of the Labour Protection Act (ArbeitnehmerInnenschutzgesetz, ASchG). It is paramount to avoid dust formation in the air (i.e. extraction instead of blowing methods for cleaning woodworking benches) or to use appropriate technological systems (extraction, filtering, ventilation of air) in order to come to grips with this problem. Only if all of these measures have not produced the desired effect recourse will be taken to person-based measures, such as wearing respirators.