Presentation on theme: "Chris Dore AEA Energy and Environment Uncertainties in the UK Heavy Metal Emissions Inventory UK Emissions Inventory Programme Funded by Defra: RMP2106."— Presentation transcript:
Chris Dore AEA Energy and Environment Uncertainties in the UK Heavy Metal Emissions Inventory UK Emissions Inventory Programme Funded by Defra: RMP2106
1. Principles of Uncertainty Combination of uncertainties Point sources- combination of random independent errors Area sources- one EF, prone to bias.
1. Principles of Uncertainty
2. Combustion Sources Solid Coal, Coke, Anthracite & SSF Important for As, Cd, Cr, Pb, Be and a major source of Mn, Hg & Se Point Sources Well characterised, and emissions data are reported. Hence no bias is expected. But possible issues associated with extrapolation of few measurements Concentrations (ppm) of metals in bituminous coals (Smith 1987)
2. Combustion Sources Solid Coal, Coke, Anthracite & SSF In 2005, over 2/3 of UK steam coal was imported ~80% from Russia/South Africa, 13% from Columbia/Indonesia. Distribution with the ranges shown is not known. Fugitive emissions from Coke Ovens Area Sources Median values taken from a wide range Fuels assumed to be the same as coal Limited information on PM control Potential for significant bias
2. Combustion Sources Petroleum Petroleum Fuels Important for all metals except Cr and Hg, major sources of Be, Cd, Ni, Se, V & Zn Metal emissions are primarily associated with petroleum coke, waste lubricants & fuel oil (higher metal contents) However, large volumes of gas oil, DERV and petrol are consumed, giving notable contribution, despite their lower metal contents. Point Sources Variability would result in little impact on emissions total Area Sources Metal content taken from literature values Fuel oil: variability of 2-4 times the mean value Gas oil/DERV: very variable metal content data Waste lubricants (10% of Pb): factor of ~10 variability metal content
2. Combustion Sources Pb in Petrol Pb in Petrol, and Unleaded Petrol UK uses EF’s based on measurement data Pb content of “unleaded” = 0.04 mg/l (UKPIA 2003) 70% assumed to be released to air Small when compared to the limit value (5 mg/l)
2. Combustion Sources Burning of CCA Treated Wood “CCA” Cu, Cr As treated wood. Major source for As, important for Cr Data available on As consumed in CCA preservatives. But v difficult to estimate the quantities of wood burned Cr and Cu emissions extrapolated from As data Estimates could be out by a factor of 20. Cremation Well characterised in the UK Uncertainties of Hg would give a maximum impact of 10% increase to the UK total. Other Fuels Scrap tyres, MSW and wood in power stations Not a particularly large source
3. Non-Combustion Sources Metal Industry Processes Important for most metals Includes processes at steelworks (sintering and blast, basic oxygen, & electric oxygen furnaces), foundries, 1° Al production, 2° Pb & Al production, and various other non- ferrous metal processes Variety of point source data and literature data. Estimates are likely to only include stack emissions, and fugitives are therefore not accounted for. Chloroalkali Processes Important for Hg The main source is associated with the ventilation air from the cell room Very difficult to asses for a variety of reasons, assume that the emission could be underestimated by a factor of five (also used for other fugitive emissions)
3. Non-Combustion Sources Tyre & Break Wear Important for Zn and Cu Estimates are a fixed fraction of PM 10 emission from these sources Tyre wear is easy to estimate, but PM 10 emission less so. UK specific data. Metal concentrations in tyres are highly variable (less so for HGV’s). Metal content of brake linings is fairly well characterised. Emissions per vkm vary by nearly an order of magnitude. UK specific data. “Odd and Ends” A variety of other sources included in the inventory (fireworks, glass manufacture, waste incineration etc.)
4. Missing & Non-anthropogenic Sources “Missing” Sources Accidental/malicious fires dwellings, factories, other buildings, vehicle fires Demolition Corrosion/abrasion of metal structures Galvanizing Non-thermal processing of scrap metals e.g. shredding of scrap metals Part B industrial processes e.g. cement batching, quarrying, powder coating Abrasion of road surfaces by motor vehicles
4. Missing & Non-anthropogenic Sources Non-anthropogenic Sources Natural Sources not currently included or estimated. Estimates available from Ilyin & Travnikov (2005) Marine Sources not currently included or estimated. Estimates available from Ilyin & Travnikov (2005) Resuspension Estimates available from Ilyin & Travnikov (2005) suggest significant contributions for Pb and Cd (trebling the 2004 Cd emissions in the UK). However estimates from Vincent and Passant (2006) for Cd, Pb, As, Ni suggested resuspension was not a major source.
5. Mapping Emission Estimates
6. Conclusions Conclusions There are areas where improvements need to be made However we are currently limited by data availability Recommendations for Future work Point Sources: Obtain more information on whether fugitive emissions are included in current estimates Combustion Sources: Obtain more comprehensive data on metal content of fuels Brake and Tyre Wear: Review and consolidate existing literature information “Missing” Sources: Make some initial estimates by improving PM 10 estimates (not straightforward!) Natural Sources: Incorporate estimates into emissions inventory Validation & Verification After conducting these improvements, reassess the estimates derived from modelling in light of updated emissions inventory estimates.