Dust

Up to 50% of the dust that occurs indoors originates in the outdoor air. Other sources of dust in the rooms used include dust attached to shoes and clothes, sedimented particles being raised or disturbed mechanically (e.g. when vacuum cleaners are used or paper is handled) and work equipment. The concentration and composition of indoor dust varies significantly depending on how the room in question is used. For instance, large deposits of dust in rooms that are otherwise cleaned normally or situations in which large quantities of paper are handled, e.g. archives and during copy processes are an indication that the dust levels in the ambient air will be high.

Possible deposits of semi-volatile organic compounds (SVOCs), biocides, polycyclic aromatic hydrocarbons (PAHs), plasticizers, etc. may be more of a problem than the dust itself. These substances may have noxious or irritative effects or be harmful to health.

The recommended practice for assessing dust exposure in indoor workplaces is to use the PM2.5 and PM10 fractions defined for environmental protection purposes since the indoor concentration levels are mainly influenced by the outdoor air, for which assessment values are available. The German Committee on Indoor Guide Values suggests that, where there are no combustion processes (e.g. tobacco smoke), the 25 μg/m³ daily value defined by the WHO be used as the assessment value for the PM2.5 fraction. In general, it should be ensured that the PM10 fraction concentration does not exceed the EU dust limit for tropospheric air of 50 μg/m³.

In order to reduce indoor dust exposure rooms should be sufficiently ventilated. In addition, every effort should be made to find and minimize known sources of particular matter.