Impact of operating wood-burning stoves on indoor air quality

A field study on the impact of operating and reloading wood-burning stoves on the indoor air quality was carried out during two consecutive winters. In contrast to the majority of recent studies, which focussed on the ambient air quality and the penetration of particles to the indoor air, this study aims to understand to what extent the operation of a stove contributes to the generation of concentration of ultrafine particles in the indoor air. Therefore, different stoves were ignited in one session by the owner of the stove and in a subsequent session by an expert on wood-burning stoves. The study was conducted in seven typical Danish detached houses without other indoor activities taking place. In each house the average air change rate during one week was measured (using passive tracer gas technique) and the indoor and outdoor temperature and relative humidity were recorded continuously for one week. The concentrations of ultrafine particles were measured for several hours. The results showed that opening the door of the stove for reloading was a major source for emission of ultrafine particles, with peak concentrations ranging from between 0.24•1011 to 2.16•1011 particles/m3. This is approximately 7 to 90 times higher than the background concentration of ultrafine particles in the houses. In addition, the results showed that the air change rates increased between approximately 2 % and 90 % after the ignition of the stoves.