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Airborne particles from wood burning in the UK

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Presentation given by Dr Gary Fuller at the 2015 Clean Air Conference, 28/09/15, Dublin

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Airborne particles from wood burning in the UK

  1. 1. Airborne particles from Wood burning in the UK Gary Fuller, Anja Tremper, Timothy Baker- King’s College London (gary.fuller@kcl.ac.uk) Karl Espen Yttri – NILU David Butterfield - NPL
  2. 2. 2 Decarbonising heating European energy projections also point to 50 - > 100% increase in biomass energy from 2010 to 2020 (IIASA, 2010) Current UK wood heating is thought to be small but there has been recent concern over increasing amounts of wood being burnt in existing fire places and future widespread installation and use of biomass boilers. UK Renewable Heat Incentive is likely to be a big driver (700,000 new biomass burners 2010 to 2020 (Klevnäs and Barker 2009) – 10,789 by end of Aug. UK planning guidance for 10% on-site renewable energy in new non- residential buildings (Merton, 2012 ).
  3. 3. 3 Biomass in schools
  4. 4. 4 A fire at the heart of a homePhotos from SIA
  5. 5. 5 Black carbon, health and climate Black carbon is a short-term climate forcer as highlighted by recent UNEP assessment (UNEP, 2011; Shindell et al 2012; Shine et al 2007). Black carbon has been shown to be a better predictor of short-term air pollution health effects than PM mass metrics (Janssen et al 2011; 2012 - for WHO)
  6. 6. 6 But its not all good for health
  7. 7. 7 Drastic measures to manage wood burning PM
  8. 8. 8 Some experiments
  9. 9. 9 Levoglucosan Yttri et al. (2005); Simoneit et al., (1999); Fine et al., (2004) and others. • PM from cellulose (wood and paper) combustion is associated with emissions of levoglucosan (a sugar). • Emitted in high concentrations and not present in vapour. Can therefore be considered a good tracer for wood combustion PM. (New evidence of OH - degradation in summer but less so in winter Hennigan et al 2010) • Emission rates depend on type of wood.
  10. 10. 10 Aethalometer method • Aethalometers used in UK (two in London, 18 across UK ) as part of Defra black smoke network - UV 370nm and IR 880nm wavelengths • Measure eBC • Can be used to detect PM from wood smoke (Favez et al., 2009, 2010, Sandradewi et al., 2008a, 2008b, Sciare et al 2011 and others) • Depends on the assumed α for fossil (traffic) and wood burning • Can be thought of as wood smoke is coloured but other sources are not
  11. 11. 11 Levoglucosan ~6 weeks in middle of heating season 2010, 38 km transect Mean = 176 ng m-3 cf 15 European studies 60 - 900 ng m-3 (Szidat et al 2009) Suburbs minus central = 30±26 ng m-3 (k=2, ~2σ) or 19±16% of the inner London concentration. Similar gradients between suburbs and central city were found in Berlin by Wagener et al 2012.
  12. 12. 12 Where’s it coming from? Temperature and levoglucosan badly correlated, R2 ranging between -0.15 and -0.22 Close correlation between locations could point to sources far away? 0 1 2 3 4 5 6 7 8 9 0 100 200 300 400 500 600 700 800 DailymeantemperatureoC Levoglucosanngm-3 Bexley Greenwich Islington Westminster Kensington Ealing Temperature
  13. 13. 13 Where’s it coming from? Variation with wind speed along with tracers for urban and long-range sources 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Relativemeanconcentration Mean wind speed m s-1 Sulphate Levoglucosan Ethane Babs (wb)(370) Babs (ff)(880)
  14. 14. 14 Estimating eBC and PM concentrations from wood burning Levoglucosan PM: PM emission rates depend on wood type. •Puxbaum et al., (2007) suggested 7.35 and an OC to OM factor 1.4 and levoglucosan to EC of 0.9. Implies Levoglucosan to PM ratio of 10. •Within the range suggested by Szidat et al., (2009) of 5.5 to 14 Black carbon: from apportioned absorption in the IR wavelength and the aethalometer default mass absorption co-efficient, assuming this applies to BC from all sources. Aethalometer PM: Literature factors from multiple linear regressions with EC and OM. Favez et al., (2009, 2010), Sandrewi (2008), Sciare et al., (2011), Harrison et al., (2012).
  15. 15. 15 Estimating concentrations [PM wood Aethalometer] = (0.95 ± 0.0) [PM wood levo] + (0.06 ± 0.14), r = 0.92 n= 42 -1 0 1 2 3 4 5 PM10fromwoodburningμgm-3 PM from levoglucosan PM from aethalometer model
  16. 16. 16 UK mainland (aethalometer) winter time PM from wood burning (μg m-3)
  17. 17. 17 UK mainland (aethalometer) Winter time PM from wood burning (μg m-3) in Norwich
  18. 18. 18 UK mainland (aethalometer) Winter evenings weekend / weekday
  19. 19. 19 Myth busting – The smoke just drifts away...? Winter in a modern house with gas heating……. . -2 0 2 4 6 8 10 12 14 16 18 15:00 15:15 15:30 15:45 16:00 16:15 16:30 16:45 17:00 17:15 17:30 17:45 18:00 18:15 18:30 18:45 19:00 19:15 19:30 19:45 20:00 20:15 20:30 20:45 21:00 21:15 21:30 21:45 22:00 22:15 22:30 22:45 23:00 23:15 23:30 23:45 00:00 00:15 00:30 00:45 01:00 01:15 01:30 01:45 02:00 02:15 02:30 02:45 03:00 03:15 03:30 03:45 04:00 04:15 04:30 04:45 05:00 05:15 05:30 05:45 06:00 06:15 06:30 BCugm-3 One winter's Sunday afternoon and evening in Gary's House Outfor a walk around the neighbourhood (late Victorian terraced houses) ~1 in 5 houses with visable smoke fromchimneys Did stir fry for tea. Turned off heating closed interior doorsdownstairs changing ventilation Returned home
  20. 20. 20 Conclusions Good agreement method to assess wood burning PM Mean levoglucosan to mannosan ratios were 7.1 -7.8 across the six London sites suggesting a mixture of hard and soft wood burning Wood burning is mainly winter source. Mean wintertime PM from wood between 1.1 and 2.5 µg m-3. Across ten UK cities wood burning comprised ~2 - 7 % of annual mean PM10 and 3 - 13% in wintertime. PM wood in London comes from within the city and is greatest at weekends and in the evenings suggesting that wood burning is a secondary domestic heating source. Similar patterns across the southern half of England. Likely that PM from wood burning is mainly from domestic wood burning in existing fire places (NB: no incremental levoglucosan at Islington Arsenal next to modern wood burner but little wind from the right direction!) Smoke control legislation in London and other cities (like Bath) isn’t working Year on year changes hard to determine from these tracers and short time scales but more likely to be an increase than decrease (wood smoke will be almost all PM2.5 – EU exposure reduction)
  21. 21. 21 Conclusions Can increased wood burning undo the substantial investment being made to control exhaust emissions? At 1.1 μg m-3, annual mean PM10 from wood burning in London is far greater than the PM10 reduction of 0.17 μg m-3 predicted from the first two phases of the London Low Emission Zone. Winter-time PM10 from wood burning in suburban Paris exceeds that from traffic (AirParif, 2014) In Duisburg, Germany, wintertime PM from wood burning is the same as that from traffic (Hellich, Kuhlbusch et al 2015)
  22. 22. 22 DEFRA 2010 Conclusions
  23. 23. 23 Thanks… My colleagues Timothy Baker and Anja Tremper for loads of hard work on the ground. London boroughs of Greenwich, Bexley, Central London cluster group and defra for having the foresight to fund the Levoglucosan measurements and Ealing for hosting 2010 sampling. Jean Sciare,Oliver Favez, Phil Hopke, Grisa Mocnik and Tony Hansen for enjoyable and helpful discussions. Defra and our NPL partners (especially David Butterfield) in the black smoke network for the absorption measurements. Karl Espen Yittri for levoglucosan analysis and comments on the project.
  24. 24. 24 Contact and papers gary.fuller@kcl.ac.uk

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