Assessment of the contribution from wood burning to the PM10 aerosol in Flanders, Belgium

• Published in: The Science of the total environment Vol. 437; pp. 226 - 236
• Main Authors: Maenhaut, Willy, Vermeylen, Reinhilde, Claeys, Magda, Vercauteren, Jordy, Matheeussen, Christina, Roekens, Edward
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-10-2012; Elsevier
• Subjects: Aerosols; air; Air Pollution - analysis; anhydrides; Applied sciences; Atmospheric pollution; autumn; Belgium; Biomarkers - analysis; burning; carbon; Combustion and energy production; Environmental Monitoring - methods; Exact sciences and technology; filters; gas chromatography; Glucose - analogs & derivatives; Glucose - analysis; hardwood; labeling techniques; Levoglucosan; mass spectrometry; Monosaccharide anhydrides; monosaccharides; Monosaccharides - analysis; Organic carbon; Organic Chemicals - analysis; Particle Size; Particulate Matter - analysis; PM10 mass; Pollution; Pollution sources. Measurement results; seasonal variation; Seasons; softwood; spring; summer; winter; Wood; Wood burning; Belgium; Europe; Levoglucosan; Organic carbon; Monosaccharide anhydrides; Wood burning; PM10 mass; Oside; Hardwood; Softwood; Combustion; Organic anhydride; Biomass; Molecular marker; Spatial variation; Fuelwood; Pollutant emission; Coarse particle; Seasonal variation; Pollution source; Aerosols; Air pollution; Emission measure; Organic compounds
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2012.08.015

From February 2010 to February 2011 PM10 aerosol samples were simultaneously taken every 4th day at 7 monitoring sites in Flanders, Belgium. Two of the sites (i.e., Borgerhout and Gent) were urban background sites; one (i.e., Mechelen) a suburban background site, and the other four (i.e., Hamme, Lier, Retie, and Houtem) rural background sites, whereby Hamme and Lier were expected to be particularly impacted by biomass burning. The samplings were done for 24h and 47-mm diameter Pallflex® Tissuquartz™ 2500 QAT-UP filters were used. After sampling the PM10 mass concentration was determined by weighing; organic and elemental carbon (OC and EC) were measured by thermal–optical transmission analysis and the wood burning tracers levoglucosan, mannosan, and galactosan were determined by means of gas chromatography/mass spectrometry. The atmospheric concentrations of levoglucosan and the other two monosaccharide anhydrides showed a very clear seasonal variation at each site, with highest levels in winter, followed by autumn, spring, and summer. The levoglucosan levels for 5 of our 7 sites (i.e., Retie, Lier, Mechelen, Borgerhout, and Gent) were very highly correlated with each other (all between site correlation coefficients r>0.9, except for one value of 0.86) and the levels in the parallel samples of these 5 sites were similar, indicating that wood burning at these 5 sites was a regional phenomenon and that it was taking place in many individual houses on similar occasions (e.g., on cold days, weekends or holidays). The levoglucosan levels at Houtem and the correlation coefficients of the 5 sites with Houtem were lower, which is explained by the fact that the latter site is at less than 20km from the North Sea so that the air there is often diluted by rather clean westerly maritime air. A peculiar behavior was seen for Hamme, with on many occasions very high levoglucosan levels, which was attributed to the fact that there is wood burning going on in several houses nearby this site. From our levoglucosan/mannosan ratios we derived the relative contributions of softwood and hardwood burning, thereby following the same approach as used by Schmidl et al. (Atmos Environ 2008;38:126–41). It was found that softwood burning accounted, on average, for about 70%, and there was little variation in this percentage with site or with season. The levoglucosan data were used to assess the contribution of wood burning to the OC and to the PM10 mass, again following the approach of Schmidl et al. (2008). The annual average contributions of wood burning OC to the PM10 OC were in the range of 20–25% for 6 of our 7 sites and 36% for Hamme; the averages for summer were 2.0–3.9% for the 6 sites and 14.5% for Hamme; the corresponding data for winter were 36–43% and 60%. As to the contribution from wood burning to the PM10 mass, the annual averages were in the range of 4.8–6.3% for 6 of our 7 sites and 13.3% at Hamme; the averages for summer were 0.51–1.14% for the 6 sites and 5.0% for Hamme; the corresponding data for winter were 8.6–11.3% and 22%. Our finding that wood burning is an important contributor to the OC and the PM10 mass, especially in winter, is in line with published data from various other sites in other European countries.
► A one-year study with 7 sampling sites and a total of 644 daily PM10 samples. ► PM10 mass, elemental carbon, organic carbon (OC), and 3 anhydrosugars determined. ► Wood burning in Flanders appears to be a regional scale phenomenon. ► Wood burning is an important contributor to the PM10 OC and PM10 mass in winter. ► Less wood burning would help in complying with the European air quality legislation.