Experimental study on the impact of ventilation parameters on pollutant transfer from outdoor air into a dwelling.

In urban areas, people stand the most of their time in indoor environment. In this context, indoor air quality is more and more a subject of concern. Outdoor air quality can have a large impact on indoor air quality. An experimental study has been conducted into a dwelling, in collaboration between the LHVP and the CSTB, in order to study the indoor concentration of pollutants depending on the outdoor pollution and the air renewal due to ventilation system. Different experiments have been conducted in an empty dwelling situated in a polluted area in Paris during winter and summer periods. The measured pollutants were indoor and outdoor CO, SO2, NO, NO2, O3, VOC, PM2.5 particles and black smoke index. Additional measurements have been performed as meteorological conditions (wind speed and direction, external and internal temperature and humidity). The pollutants sampling time steps were comprised between two minutes and one hour depending on pollutant. The transfer of the pollutants has been tested as regards different ventilation strategies. Air renewal of the dwelling was thus controlled : the dwelling has been air tight and the residual air leakage has been characterised using blower door and tracer gas technique. A mechanical ventilation system has been installed in the dwelling in order to have two controlled extract flows. During the summer experiments, measurements have also been carried out with opened windows. This paper presents the impact of ventilation parameters on outdoor pollutants transfer. The results of the study are the part of the outdoor pollution entering in the dwelling, versus the ventilation air renewal. On the basis of these experiments, we have also developed a methodology to assess the air renewal. We adjust the air change rate by comparison between the indoor concentration measurements of carbon monoxide and calculations based on outdoor concentration measurements of carbon monoxide using computer code Siren2000.