Characterization of real-life benzo(a)pyrene emissions of residential wood combustion furnaces

Abstract

Residential wood combustion is an important source of various pollutants. Polycyclic aromatic hydrocarbons (PAHs) are particularly toxic. The objective of this work is to contribute to the knowledge about real-life PAH emissions from residential wood combustion.A simplified measurement method for benzo(a)pyrene (BaP), the guiding compound for PAHs, was developed which was then applied for the measurements at six automatic boilers, six log wood stoves, four pellet stoves, three log wood cookers and another log wood stove at which measurements with two oxidative Pt/Pd-catalysts were conducted. While at boilers emission measurements were conducted at start, stop, nominal load and part load operation respectively for stoves and cookers operation protocols that reflect real life operation were applied. For the tests with the catalysts a test stand which allows synchronous measurements of differently treated flue gas was used. Beside BaP also other emissions like organic gaseous compounds or total suspended particles were determined. In the boiler tests it was shown that start and stop operation decisively impact total BaP emissions. The stove tests indicated that clearly lowest BaP values (<1 μg MJ-1) can be achieved by pellet stoves, whereas the remarkably highest BaP value (130 μg MJ-1) as a consequence of unfavorable conditions during start also was measured at a pellet stove. The importance of respecting unfavorable combustion phases for the assessment of real life emissions was clearly demonstrated. The tests with the Pt/Pd-catalysts indicated the high potential of PAH reduction as BaP was reduced at maximum by 83%.