Air change and contaminant distribution in a ventilated space and in particular in the near zone of a human being is essential for the air quality of the inhaled air. In order to use the ventilation air effectively it must be distributed to the parts of the room where people are present. This is important both from energy and health aspects. The increased frequency of allergy in the population has emphasised this even more.
With a displacement ventilation system the air is supplied with a small undertemperature, compared to the room air, and with a low velocity at a low level in the occupied zone and enters the room like water in a bathtub. The air distribution in the room is then governed by the convection flows created in the room from people, computers and other heat sources.
In displacement ventilation there is an open question whether the particles deposited on the floor are resuspended into the ventilation airflow and following the rising convection flows close to the human being.
This paper will present experimental results of the contaminant distribution in the near zone of a human being and the occurrence of small particles in the inhaled air. A simulator of a human being is used in order to study the transportation of particles from the floor area without particles emitted from the human influencing the measurements. The influence of movements and activities in the room is studied. This paper will answer the questions whether there is a transport of particles (fraction of particles) from the floor to the breathing zone, which fractions and if this only is the case when there is a movement in the room.