Dust in museums and depositories can be harmful for materials stored there. Dust particles not only cause soiling, but coarse particles can damage surfaces by abrasion and fine particles of acidic or alkaline character may cause chemical degradation or moistening due to their hygroscopicity.
Indoor air quality was evaluated in the exposition of prehistory of the National Museum (NM) in Prague and in the depository of historical textile of the NM in Terezín. The results indicated traffic emissions penetrating indoors from the outdoor air as a main source of fine particulate matter indoors at both localities and visitors as an important source of coarse particles in the exhibition hall in Prague.