Transfer of ultrafine particles and air in multi-storey buildings

An emerging issue in Denmark is passive smoking in residential buildings where non-smokers are exposed to harmful smoke from their neighbours. There are various ways that smoke infiltrates from one flat to another. The air infiltration rate between two flats in a multi-storey building depends on its construction, tightness and age.
This paper presents some of the results from of a study with transfer of ultrafine particles and tracer gas carried out in an older multi-storey building in Copenhagen. The aim of the study was to quantify the transfer of ultrafine particles and gases from one flat to another flat before and after sealing of the floor. The floor between the two flats was sealed using a new floor sealing method. The sealing method is developed by a specialist firm in sealing.
Indoor ultrafine particle concentrations and tracer gas were measured continuously in the two flats during the measuring periods. The gas source was N2O and the particle source was burning cigarettes in the unoccupied flat. Reduction of the concentration of ultrafine particles and gases by sealing the floor with polyethylene and joint filler of bitumen was studied.
It was evaluated how the sealing performed with regard to decreasing the amount of transferred ultrafine particles and a tracer gas between two flats separated by a floor. When the floor between the flats was not sealed, the results showed that the transfer of ultrafine particles was about 4% and the transfer of tracer gas was 14%. After sealing, the transfer was reduced to 1.6% and 5% respectively.