Indoor aerosol exposure has become of major interest since health hazards arising from fine and ultrafine dust particles have become more evident. The study presented here is dedicated to fine and ultrafine dust characterization and determination in more than 150 private residences with special respect to a phenomenon of enhanced soiling. In the scientific community committed to ecological housing and building it is referred to as "black magic dust" though the staining is often film-like in nature. This phenomenon has been observed for 20 years in residences in Europe and North America and there is strong evidence that it is correlated to emission of semivolatile organic compounds (SVOCs) from refurbishing materials. In this study we show that fine dust particle concentrations are elevated in such homes and that there is characteristic particle morphology for "black magic dust" staining. From the results we suggest that elevated particle concentration and particle size are significant to induce a condensation process which causes the observed blackening. Reduced air exchanges due to new insulation standards may also contribute to its occurrence.