air quality monitoring：空气质量监测

Review of the Potential Impact on Air Quality from Increased Wood Fuelled Biomass Use in London,Peter Coleman,Acknowledgements,Ruth Calderwood from City of London and Jareed Boow from London CouncilsColleagues who did all the work; Robert Stewart, John Abbott, Alan Leonard, Alan Collings, Pat Howes and Nick Barker.,Great Smog December 1952,Desired Air Quality,Scope of London Report,commissioned by London Councils via the City of LondonDrivers for increasing use of biomassLegislation and potential controls on biomass plantSustainability and transport impactsCombustion technologiesFuelsAir quality impacts of renewable scenariosA toolkit for the assessment of planning applications for biomass heating,Pollutants Associated with Biomass,Nitrogen oxidesPolyaromatic hydrocarbons (PAHs) formed from incomplete combustion Metals when treated wood is burned As, Cu, Cr(VI)Dioxins where waste or treated wood (PCP/ lindane) is burnedParticles (PM10 / PM2.5) Coarse material entrained chars, fine alkali metal salts Poor combustion increases coarse particle emissionsModern plant emissions lower and TSP PM10 PM2.5Abatement therefore difficult,Pollution Control Regulation for Biomass,IPPC A(1)50MW combustion plant burning any fuel 3-50MW combustion plant burning fuels containing or derived from waste1te/hour incineration of wasteLA-PPC A(2)Co-incineration of non-hazardous waste associated with any A(2) process less than 50MWIncineration of non-hazardous waste in an incineration plant with a capacity 35 times/year40 ug/m3 annual meanPM2.5 18 times/year40 ug/m3 annual meanPAHs0.25 ng BaP /m3 by 2020, EU target 1 ng BaP/m3 by 2012,Size Distribution (Erlich et al. 2007),Clean Air Act Emission Limits,Comparison of EU Measurement Methods,Emission Limits elsewhere,Toolkit,AnywhereIs the appliance permitted?Is it a 45.4 kg/h (approx 120 200kW)?If so, then agreed abatement equipment must be used; andChimney height must be determined unless AQ impact shown to be so far as practicable not prejudicial to health.If within a smoke control area then an exempt appliance,Approach,ADMS used to predict ground level concentrations for a unit emission rate from stacks between 10.6 and 40m and diameters from 0.1-1mStack at centre of 10m cube buildingDischarge temperature 100oCDischarge velocity sufficient to overcome pressure dropHeathrow 2005 metrological data1m roughness1km x1km 10m grid receptors 24 model scenariosAnnual mean, 90th %ile 24h mean, 99.8th %ile hourly mean Emission rate for 1 ug/m3 estimated,Requirements from Developer,OS grid coordinates of stackHeight of stack above groundDiameter of stackDimensions of buildings within 5 stack heightsDescription of the combustion appliancesDescription of abatement equipmentMaximum rates of emission of particles and NOx (not necessarily at capacityIf size fractionated PM available use if not all PM2.5.,Annual mean NO2 /PM 1 ug/m3,99.8th %ile hourly NO2 of 40 ug/m3,Modelled NOx 2020 Scenario 1 Increment,Modelled NOx 2020 Scenario 3 Increment,Process PM10,Calculate a background adjusted emission rate EA EA = E/(32-G)E = emission rate; G annual average background concentrationIf existing concentration 32 thenEA= E/delta C Where delta C is maximum allowed incrementUse Nomagraph to estimate effective stack heightIf this is 3m above any adjacent area to which there is general access, calculated effective stack height, any building within 5 stack heights,Process PM2.5 /NOx,Calculate a background adjusted emission rate EA EA = E/(25-G)As beforeNOx EA = E/(40-G) annual meanEA = E/(200-G) hourly averageMinimum chimney height is the tallest of the three calculated,Example,A 500kw wood boiler in a building 30m high by 20m square. Stack diameter 0.5mParticle emission rate from CAA 0.048 g/sNOx from Corinair gives 0.075 g/s,90th %ile 24 hour mean PM10 1 ug/m3,Annual mean NO2 /PM 1 ug/m3,NO2,PM2.5,99.8th %ile hourly NO2,Example (cont.),Critical effective stack height less than 2.5 x building heightFrom CHMBuilding width B =root (202+202) = 28.3 mLesser of building height (30m) and width K = 28.3 mT = 30 + 1.5 x 28.3 = 72.5mT corrected stack height soCorrected chimney height C = 30 +9.5 x (1-(30/72.5) = 35.6 mRequired stack height 35.6m (5.6m) if no taller buildings within 47.5m of stack,Screening Assessment for Domestic Biomass,Seeks to identify maximum density of domestic solid fuel use before exceeding PM2.5 objectiveEstimate number of solid fuel using houses in 500m x 500m square Weight houses Ceq = C + 0.36 anthracite + 0.56 SSF + 0.79 wood Estimate proportion of open space LDeq = Ceq/(1-L)If Deq D then PM2.5 objective unlikely to be exceeded,Nomograph for Risk of Exceeding for PM2.5,Validation with 2003 NOx Meas