Emissions from Wood Burning Stoves and Ethanoi Fireplaces into the Indoor Environment

摘要

Background: The use of combustion heat sources regained importance in the past years due to increasing energy costs. In contrast to enclosed wood burning stoves (WBS), the use of open ethanol-based fireplaces is a common decoration trend. However, all combustion products these devices generate are released into the indoor environment. While the outdoor emission from WBS is strictly regulated in Germany, the indoor release of combustion products is rarely considered. Methods: 8 ethanol fireplaces (3 liquid, 5 gel) were tested in a 48 m3 emission test chamber according to the recommendations of the manufacturer and DIN 4734-1. The following parameters were monitored: Particles (5 nm - 20 μm), NOx, CO, CO2, HCHO. VOCs were measured discontinuously. 6 WBS were tested in private homes between Nov 2012 and Feb 2013. The indoor air quality was monitored before, during and after operating the WBS. In addition to the mentioned parameters PAH and PM2.5 were determined indoors and outdoors. Results: Operating the ethanoi fireplaces significantly affected the indoor air quality. During the operation of some devices the German guidance values for CO2 (2000 ppm) and NO2 (350 $1g/m~3) were exceeded. Few systems showed considerable release of HCHO. Ethanoi fireplaces as well as WBS were significant sources for ultra-fine particles. The expected human exposure against particles was estimated on the basis of the ICRP lung deposition model and compared with outdoor air exposure. An increase of benzene and PAH in indoor air was detected during the operation of some WBS. Conclusions: The results of this orienting study illustrate that ethanoi fire places and WBS are important sources for indoor air contaminants. Especially under the aspect of lowering indoor air exchange rates (energy saving) and increasing use of fuels with net zero carbon footprint this is a topic of high importance. With regards to consumer safety, future product developments should focus on indoor air quality in addition to the present fire protection requirements.