Assessment of the contribution from wood burning to the PM10 aerosol in Flanders, Belgium Willy Maenhaut1,2, Reinhilde Vermeylen2, Magda Claeys2, Jordy Vercauteren3, Christina Matheeussen3 and Edward Roekens3 1 Ghent University (UGent), Department of Analytical Chemistry, Krijgslaan 281, S12, 9000 Gent, Belgium 2 University of Antwerp (UA), Department of Pharmaceutical Sciences, Universiteitsplein 1, 2610 Antwerpen, Belgium 3 Flemish Environment Agency (VMM), Kronenburgstraat 45, 2000 Antwerpen, Belgium Wood burning in PM10, Flanders 1 Introduction In Flanders (Belgium) we are struggling with too many exceedances of the 50 µg/m3 daily PM10 mass limit ¾ in the EU : only 35 exceedances per year allowed at any given location ¾ thus, of interest to examine the cause of possible exceedances Wood burning may provide a substantial contribution to the PM10 aerosol mass, as appeared from studies in several European countries (e.g., Switzerland, Austria) Over a decade ago, Simoneit et al., AE [1999] introduced levoglucosan as an indicator for wood burning ¾ levoglucosan (C6H10O5) arises from the pyrolysis of cellulose, the main building material of wood, at temperatures higher than 300 °C ¾ levoglucosan is accompanied by other minor stereoisomeric monosaccharide anhydrides in atmospheric aerosols, with mannosan and galactosan being the most important ones Flemish Environment Agengy (VMM) wanted to find out what the contribution from wood burning to PM10 was over a full year for 7 sites in Flanders ¾ thereby using levoglucosan as wood burning indicator Wood burning in PM10, Flanders 2 Sampling From 7 February 2010 to 6 February 2011 PM10 aerosol samples simultaneously taken every 4th day at 7 monitoring sites in Flanders, Belgium ¾ on 47-mm diam. Pallflex quartz fibre filters Two of the sites (i.e., Gent and Borgerhout) are urban background sites; Mechelen is a suburban background site, and the other 4 sites are rural background sites, whereby Hamme and Lier were expected to be particularly impacted by biomass burning Wood burning in PM10, Flanders 3 Borgerhout : at 30 m from a busy road (Plantin en Moretuslei) Most polluted of the 2 urban background sites Wood burning in PM10, Flanders 4 Gent : in the Baudelo park in the North-East of the city Least polluted of the 2 urban background sites Wood burning in PM10, Flanders 5 Hamme : in a rural area with individual houses In the neigbourhood of the site are several inhabitants who use wood as fuel Wood burning in PM10, Flanders 6 Houtem : rural background site In the middle of an agricultural area in the polders Wood burning in PM10, Flanders 7 mm, °C Meteorology 10 15 20 25 30 35 40 0 5 03-Feb-10 15-Feb-10 27-Feb-10 11-Mar-10 23-Mar-10 04-Apr-10 16-Apr-10 Of the92sampling days:60dayswithrain 28-Apr-10 10-May-10 22-May-10 Wood burning inPM10, Flanders 03-Jun-10 15-Jun-10 27-Jun-10 Precip. 09-Jul-10 21-Jul-10 02-Aug-10 Temp. 14-Aug-10 26-Aug-10 07-Sep-10 Wind dir. 19-Sep-10 01-Oct-10 13-Oct-10 25-Oct-10 06-Nov-10 18-Nov-10 30-Nov-10 12-Dec-10 24-Dec-10 05-Jan-11 17-Jan-11 29-Jan-11 10-Feb-11 0 45 90 135 180 225 270 315 360 8 Wind dir. (degrees) Meteorology (cont.) 25 20 15 10 Number of days 5 19 10 2 7 21 18 7 8 0 NNE ENE ESE SSE SSW WSW WNW NNW (0-45) (45-90) (90-135) (135-180) (180-225) (225-270) (270-315) (315-360) Wind direction mostly from South-West and North-North-East Wood burning in PM10, Flanders 9 Analyses PM10 mass determined by weighing of the filters at 20 °C and 50% relative humidity [done by VMM] Organic, elemental, and total carbon [OC, EC, and TC (= OC + EC)] measured with a dual photo-detector (2PD) thermal-optical instrument from Sunset Lab ¾ using NIOSH temperature protocol ¾ transmission (TOT) and reflectance (TOR) simultaneously measured ¾ TOT data retained for further evaluation Levoglucosan, mannosan, and galactosan measured by gas chromatography / mass spectrometry (GC/MS) after trimethylsilylation, using method described in Pashynska et al., J. Mass Spectrom. [2002], but ¾ extraction with methanol ¾ use made of a different recovery standard (RS) ¾ and slightly modified GC temperature program employed Wood burning in PM10, Flanders 10 Schematic diagram of the Sunset Laboratory TOT instrument (V = valve) Wood burning in PM10, Flanders 11 Thermogram for Gent PM10 sample of 13 July 2010 (transmission) 4000 He 1200 He:O2 3500 Laser T Temp. 1000 3000 FID Split 800 2500 2000 600 1500 400 Laser T (rel. units) Laser T (rel. 1000 Temp. (°C); FID (rel. units) 200 500 OC1 PC EC 0 0 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 Time (s) OC = OC1 + PC (with PC: pyrolytic carbon) : area below the blue line prior to the OC/EC split point (vertical brown line) EC : area below the blue line after the OC/EC split point Wood burning in PM10, Flanders 12 He Thermogram for Gent PM10 sample of 13 July 2010 He:O2 8000 Laser R 1200 Laser T 7000 Temp. 1000 FID 6000 Split R Split T 800 5000 4000 600 3000 Laser (rel. units) 400 2000 Temp. (°C); FID (rel. units) 200 1000 0 0 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 Time (s) Full brown line : laser transmission (T) signal ¾ vertical full brown line : OC/EC split point for T Dashed purple line : laser reflectance (R) signal ¾ vertical dashed purple line : OC/EC split point for R Wood burning in PM10, Flanders 13 Wood burning in PM10, Flanders 14 Total ion current (TIC) chromatogram [relative abundance (R.A.) versus time] obtained for the sample that was collected on 23 February 2010 in Hamme. The numbered peaks are for the following compounds: 1: galactosan: 60.6 ng/cm2; 2: mXP: 510 ng/cm2 (added); 3: mannosan: 145 ng/cm2; 4: levoglucosan: 826 ng/cm2. Wood burning in PM10, Flanders 15 ECTOR/ECTOT Comparison ofTOTandTORresults 0 1 2 3 4 5 6 03-Feb-10 TOR providedsystematically 15-Feb-10 ¾ 27-Feb-10 thus, TORprovidedsystematically lowerOCdatathanTOT 11-Mar-10 23-Mar-10 Houtem, N029 Retie, RT01 Lier, LR02 Hamme, HA02 Mechelen, ML01 Gent, R701 Borgerhout, R801 04-Apr-10 16-Apr-10 28-Apr-10 10-May-10 Wood burning inPM10, Flanders 22-May-10 03-Jun-10 15-Jun-10 27-Jun-10 09-Jul-10 largerECdatathanTOT 21-Jul-10 02-Aug-10 14-Aug-10 26-Aug-10 07-Sep-10 19-Sep-10 01-Oct-10 13-Oct-10 25-Oct-10 06-Nov-10 18-Nov-10 30-Nov-10 12-Dec-10 24-Dec-10 05-Jan-11 17-Jan-11 16 29-Jan-11 10-Feb-11 TOR/TOT ratio for EC as a function of season 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 TOR/TOT ratio for EC for ratio TOR/TOT 0.6 0.4 0.2 1.4 1.4 1.3 1.4 1.5 1.5 1.6 1.3 1.4 1.8 1.6 1.7 1.5 1.4 1.7 2.0 2.0 2.0 2.0 2.6 1.7 1.8 1.6 1.7 2.1 1.9 2.0 1.9 1.9 2.2 1.5 1.5 1.4 1.5 1.5 0.0 Borgerhout Gent Mechelen Hamme Lier Retie Houtem ALL Spring Summer Fall Winter Some tendency for higher ratios at rural sites than at urban sites ¾ exception: Houtem Some tendency for higher ratios in winter than in the other seasons Wood burning in PM10, Flanders 17 TOR/TOT ratio for OC versus TC loading on filter 9 8 7 y = 0.0002x2 + 0.0148x + 1.297 R2 = 0.2709 6 TOT /EC 5 TOR 4 EC 3 2 1 0 0 102030405060708090 TC (µg/cm2) Wood burning in PM10, Flanders 18 PM10 mass (µg/m3) Time seriesforthePM10massat 7sites 100 110 10 20 30 40 50 60 70 80 90 0 03-Feb-10 15-Feb-10 27-Feb-10 At Gent: 3samplesin a rowinJulywith elevatedlevels Fairly goodcorrelation betweenthedataof 7sites 11-Mar-10 Houtem, N029 Retie, RT01 Lier, LR02 Hamme, HA02 Mechelen, ML01 R701 Gent, Borgerhout, R801 ¾ 23-Mar-10 04-Apr-10 these samples takenduring the“Ghent CityFestival” 16-Apr-10 28-Apr-10 10-May-10 Wood burning inPM10, Flanders 22-May-10 03-Jun-10 15-Jun-10 27-Jun-10 09-Jul-10 21-Jul-10 02-Aug-10 14-Aug-10 26-Aug-10 07-Sep-10 19-Sep-10 01-Oct-10 13-Oct-10 25-Oct-10 06-Nov-10 18-Nov-10 30-Nov-10 12-Dec-10 24-Dec-10 05-Jan-11 17-Jan-11 19 29-Jan-11 10-Feb-11 Retie (RT) Lier (LR) Mechelen (ML) Borgerhout (BO) Hamme (HA) Gent (GE) Houtem (HO) Wood burning in PM10, Flanders 20 Correlation coefficients for the PM10 mass data of the 7 sites RT LR ML BO HA GE HO Retie 1 Lier 0.96 1 Mechelen 0.97 0.97 1 Borgerhout 0.95 0.96 0.97 1 Hamme 0.82 0.85 0.86 0.86 1 Gent 0.71 0.75 0.71 0.71 0.64 1 Houtem 0.74 0.75 0.74 0.70 0.61 0.65 1 3 "Ghent City Festival" samples excluded RT LR ML BO HA GE HO Retie 1 Lier 0.96 1 Mechelen 0.97 0.97 1 Borgerhout 0.95 0.96 0.97 1 Hamme 0.82 0.85 0.86 0.86 1 Gent 0.89 0.91 0.91 0.92 0.82 1 Houtem 0.74 0.75 0.74 0.70 0.61 0.75 1 Wood burning in PM10, Flanders 21 3 Time seriesforECatthe7sites ECTOT (µg/m ) 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 03-Feb-10 15-Feb-10 27-Feb-10 sites than wasthecase forthePM10 mass Clearly less correlation betweenthedata fromthedifferent EC levelshighest atBorgerhout,lowestHoutem 11-Mar-10 23-Mar-10 04-Apr-10 16-Apr-10 28-Apr-10 10-May-10 Wood burning inPM10, Flanders 22-May-10 03-Jun-10 Houtem, N029 Retie, RT01 LR02 Lier, Hamme, HA02 ML01 Mechelen, R701 Gent, R801 Borgerhout, 15-Jun-10 27-Jun-10 09-Jul-10 21-Jul-10 02-Aug-10 14-Aug-10 26-Aug-10 07-Sep-10 19-Sep-10 01-Oct-10 13-Oct-10 25-Oct-10 06-Nov-10 18-Nov-10 30-Nov-10 12-Dec-10 24-Dec-10 05-Jan-11 17-Jan-11 29-Jan-11 22 10-Feb-11 Correlation coefficients for EC data of the 7 sites RT LR ML BO HA GE HO Retie 1 Lier 0.84 1 Mechelen 0.75 0.85 1 Borgerhout 0.69 0.73 0.92 1 Hamme 0.82 0.89 0.76 0.66 1 Gent 0.52 0.63 0.66 0.56 0.62 1 Houtem 0.67 0.61 0.56 0.44 0.60 0.47 1 Wood burning in PM10, Flanders 23 Median EC/TC ratios 0.40 0.35 0.30 0.25 0.20 /TC ratio for PM10 0.15 TOT EC 0.10 0.05 0.32 0.24 0.20 0.13 0.18 0.15 0.17 0.00 BO GE ML HA LR RT HO Wood burning in PM10, Flanders 24 3 OCTOT (µg/m ) 10 12 14 16 18 Time seriesforOCatthe7sites 0 2 4 6 8 03-Feb-10 15-Feb-10 27-Feb-10 11-Mar-10