Impact of operating wood-burning fireplace ovens on indoor air quality

- Wood-burning fireplaces are potential sources of indoor air contaminants.
- Especially the concentration of ultrafine particles increases during operation.
- The effects of NOx, CO and CO2 were comparatively small.
- In addition to the combustion process itself firelighters are a potential source for benzene.
- In some case increased concentrations of benzo[a]pyrene were measured.

The use of combustion heat sources like wood-burning fireplaces has regained popularity in the past years due to increasing energy costs. While the outdoor emissions from wood ovens are strictly regulated in Germany, the indoor release of combustion products is rarely considered. Seven wood burning fireplaces were tested in private homes between November 2012 and March 2013. The indoor air quality was monitored before, during and after operation. The following parameters were measured: ultra-fine particles (5.6-560 nm), fine particles (0.3-20 μm), PM2.5, NOx, CO, CO2, formaldehyde, acetaldehyde, volatile organic compounds (VOCs) and benzo[a]pyrene (BaP). Most ovens were significant sources of particulate matter. In some cases, an increase of benzene and BaP concentrations was observed in the indoor air.The results illustrate that wood-burning fireplaces are potential sources of indoor air contaminants, especially ultra-fine particles. Under the aspect of lowering indoor air exchange rates and increasing the use of fuels with a net zero-carbon footprint, indoor combustion sources are an important topic for the future. With regards to consumer safety, product development and inspection should consider indoor air quality in addition to the present fire protection requirements.