Local improvement needed in Local improvement needed in air quality and source apportionment air quality and source apportionment John W atterson & Beth Conlan Conlan John W atterson & Beth National Environmental Technology Centre National Environmental Technology Centre
What’s in this presentation What’s in this presentation g What are your duties in an AQMA What are your duties in an AQMA g g How do you approach this task How do you approach this task g g Working out what sources are important Working out what sources are important g g How much of an improvement is needed How much of an improvement is needed g g Case studies Case studies g − assessment of road traffic and industrial releases − setting the scene for effectiveness • of some traffic management schemes • and cost benefit/effectiveness studies
What are your duties after declaring an What are your duties after declaring an AQMA? AQMA? g Section 84(1) of the Environment Act ... Section 84(1) of the Environment Act ... g − LAs must carry out further assessment of existing and likely future air quality in an AQMA g You need to assess You need to assess g − how much of an improvement in air quality needed − the extent to which different sources contribute to the problem
Outcome of this further Review and Outcome of this further Review and Assessment Assessment g Clear picture of the sources that LAs Clear picture of the sources that LAs can control or can control or g influence influence g Should ensure action plans strike a balance between Should ensure action plans strike a balance between g − contribution from the LA − contribution from other sectors
Where the improvements should be Where the improvements should be directed directed g Effective targeting of resources Effective targeting of resources g − cost effective − proportionate
How long do you have to do this? How long do you have to do this? g Section 84(2) of the Environment Act … Section 84(2) of the Environment Act … g − Must report within 12 months of designating an AQMA − Need to consult on this further Review and Assessment (Stage 4)
Basic information needed Basic information needed g Hopefully from your Stage 3 R&A ... Hopefully from your Stage 3 R&A ... g g Pollutants Pollutants g g Averaging periods Averaging periods g g Principal sources Principal sources g g Geographical extent of exceedence Geographical extent of exceedence g
Source apportionment Source apportionment g Major element - blaming others! Major element - blaming others! g ✓ Combination of sources Combination of sources ✓ - road, industry (Part A/ B), rail, airport, domestic fuel ✓ Road - what type of vehicle is main source Road - what type of vehicle is main source ✓ - HGV, buses, cars? ✓ Sources outside the district Sources outside the district ✓ - can you control these effectively?
Improvement in Air Quality Improvement in Air Quality g How to assess how much is needed? How to assess how much is needed? g ✓ modelling required modelling required ✓ ✓ look at emissions reduction e.g. in look at emissions reduction e.g. in NO NO x to deliver a to deliver a x ✓ NO 2 reduction at a receptor NO 2 reduction at a receptor ✓ background concentrations background concentrations ✓ ✓ not a linear relationship for NO not a linear relationship for NO x to NO 2 !! x to NO 2 !! ✓ ✓ needs scenario testing needs scenario testing ✓
Source apportionment - how precise? Source apportionment - how precise? g How precise? How precise? g ✓ based on model output based on model output ✓ ✓ meteorological influences meteorological influences ✓ ✓ source apportionment should be calculated in source apportionment should be calculated in ✓ rough percentage terms (nearest 5-10%) rough percentage terms (nearest 5-10%) ✓ Main aim is to be reasonable and proportionate in Main aim is to be reasonable and proportionate in ✓ reducing emissions reducing emissions
Do all the concentrations of the Do all the concentrations of the sources just add up? sources just add up? g Annual averages Annual averages g − e.g. NO 2 and PM 10 − concentrations from different sources can simply be summed g Objectives with short averaging periods and Objectives with short averaging periods and g percentile exceedences percentile exceedences − high percentile concentrations (e.g. 99.8th) cannot really be added − impacts from sources unlikely to coincide temporally or spatially
Pollutants with shorter averaging Pollutants with shorter averaging period objectives period objectives g Pollutants Pollutants g − CO (8 hour objective) − PM 10 (24 hour objective) − SO 2 (24 hour objective) − NO 2 (1 hour objective) − SO 2 (15 minute and 1 hour objectives)
SO 2 (24 hour objective) SO 2 (24 hour objective) g Major source Major source - probably industrial - probably industrial g g Background Background g − vehicle, domestic and remote industrial − TG4 suggests 24-hour background can be local annual average concentration in 2004 (half of 1996 value) g Industrial contribution Industrial contribution g − need to use dispersion modelling − sequential modelling to assess impacts from individual sources
PM 10 (24 hour objective) & PM 10 (24 hour objective) & CO (8 hour objective) CO (8 hour objective) g Assuming that the approach in LAQM.TG4(00) has Assuming that the approach in LAQM.TG4(00) has g been followed ... been followed ... g … for contribution from sources and backgrounds … for contribution from sources and backgrounds g g Then relative contributions can be derived by Then relative contributions can be derived by g disaggregating the total concentration the total concentration disaggregating
NO 2 (1 hour) NO 2 (1 hour) SO 2 (15 minute and 1 hour) SO (15 minute and 1 hour) 2 g Relative contributions can be derived by Relative contributions can be derived by g disaggregating the total concentration the total concentration disaggregating g Industrial contribution Industrial contribution g − need to use dispersion modelling − sequential modelling to assess impacts from individual sources
Sources of data for source Sources of data for source apportionment assessment apportionment assessment g Predictions on a national basis Predictions on a national basis g g Using the NAEI to get an idea in you local area Using the NAEI to get an idea in you local area g g Taking apart the results from modelling studies at Taking apart the results from modelling studies at g Stage 3 - what reduction is needed? Stage 3 - what reduction is needed? g Effects of some traffic management schemes - can Effects of some traffic management schemes - can g they achieve the reduction? they achieve the reduction?
Emission projections on a national Emission projections on a national basis basis UK Road Transport Emissions of PM10 70 60 50 Emissions (ktonnes Motorcycles LGV 40 Buses HGV 30 Cars DERV Cars petrol 20 10 0 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 20% diesel car sales; Central 1997 NRTF; Assumes Euro III emission reductions for all new vehicles in 2001, Euro IV reductions for cars, LGVs only in 2006; Fuel standards reduce emissions in 2000 & 2006 for all vehicles
NO x emissions (1970-1996) NO x emissions (1970-1996) 1970 Emissions 1996 Emissions Other Other Transport 2.3% Other Other Public Power 11.8% 2.9% Transport 21.8% 12.1% Public Power 30.1% Industry 13.6% Road Transport 32.2% Domestic Road 3.6% Transport Industry 46.9% 20.1% Domestic 2.6% Public Power Industry Domestic Road Transport Other Transport Other
Using the NAEI emissions inventory Using the NAEI emissions inventory
Limitations of NAEI emissions data Limitations of NAEI emissions data 2 Data given in tonnes/ year/ km 2 g Data given in tonnes/ year/ km g g Gives relative proportions - can determine what are the most important sources µ g/ m In the end, need concentrations - µ 3 g/ m 3 g In the end, need concentrations - g g Require some modelling to convert µ g/ m 2 to µ 3 tonnes/ year/ km 2 g/ m 3 tonnes/ year/ km
Using the results from modelling Using the results from modelling studies studies g Consider annual mean nitrogen dioxide Consider annual mean nitrogen dioxide g g Up to three possible components ... Up to three possible components ... g Background (2005) (~5 to 25 µ g/m 3 ) traffic (and/or) + industrial
Background concentrations Background concentrations g To calculate the improvement, need to know the To calculate the improvement, need to know the g background in the absence of any traffic effects background in the absence of any traffic effects g In these examples, determined from an urban In these examples, determined from an urban g background model background model µ g/ m So the reduction necessary in µ 3 from g/ m 3 g So the reduction necessary in from g traffic/ industry can be calculated traffic/ industry can be calculated
Examples Examples g Exceedences of Exceedences of annual mean NO annual mean NO 2 2 objective at g houses − near motorway − near junction − in town centre g Exceedences of Exceedences of 24-hour PM 24-hour PM 10 10 objective at houses g − near foundry in town centre 2 …. g T hink about options for reductions in N O T hink about options for reductions in N O 2 g
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