Standard images are available on the intranet For more specific images please contact Matthew Hart For PowerPoint help please contact Elizabeth Leishman The response of secondary inorganic particulate matter to precursor emission reductions in south-east England June 2006 Andrea Fraser 1,2, Prof. Helen M ApSimon 1, Prof. Richard G. Derwent 3, 1 Imperial College London 2 AEA, Harwell, Oxfordshire, UK 3 rdscientific

Outline Summary of the CMAQ simulation in south-east England 3 rd June – 9 th July Evaluation of the inorganic PM components with observations at Harwell monitoring site. Spatial interaction of inorganic PM components. Effects of SO 2 NO X or NH 3 emission reductions.

CMAQ simulation south-east England Meteorology Data from the UK Met. Office operational Unified Model (MetUM) are archived at the British Atmospheric Data Centre. Data are processed with a UM-MCIP program to create CMAQ ready files. Emissions European emissions are prepared from the x50km annual EMEP emissions UK emissions are prepared from the x1km annual NAEI emissions European Natural emissions calculated using a Biogenic Potential Inventory CMAQ V CB IV Chemistry

A1 Europe 48 x 48 km resolution 24 layers – 8 below 600m MetUM Global Meteorology 3hr time steps 40x40km (approx) 38 layers Emissions EMEP 2003

A2 Northern Europe 12 x 12 km resolution 24 layers – 8 below 600m MetUM UK Meteorology 1hr time steps 12x12km (approx) 38 layers Emissions EMEP 2003 NAEI 2003

A3 South-East England 4 x 4 km resolution 24 layers – 8 below 600m MetUM UK Meteorology 1hr time steps 12x12km (approx) 38 layers Emissions EMEP 2003 NAEI 2003

A3 South-East England Rural site Harwell Didcot Power station Heathrow Airport Southampton and Refineries on the Solent Power stations in the Thames estuary inc. Tilbury Dover and cross channel shipping lanes Central London M25

Model Evaluation Harwell 39% of model values within a factor of 2 of the observation 40% for 18 sites in SE England varying from 54% (Urban background) to 20% (roadside) Observed (TEOM) and Modelled PM 2.5 (μg m -3 ) 3 rd June to 9 th July 2006

EMEP intensive monitoring program Harwell is one of the EMEP measurement site. During June 2006 there was an intensive European monitoring program when additional PM component measurements were made. SO 4 2- SO 2 NO 3 HNO 3 NH 4 + NH 3 EMEP - Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe. Data were made available by Eiko Nemitz, CEH Edinburgh

Evaluation of SO 2 and SO 4 2- with observations at Harwell SO 4 2- SO 2 + SO 4 2- SO 2 49% within a factor of 2

Evaluation of HNO 3 and NO 3 - with observations at Harwell NO 3 - HNO 3 + NO 3 - HNO 3 18% within a factor of 2 65% within a factor of 2

Evaluation of NH 3 and NH 4 + with observations at Harwell NH 4 + NH 3 + NH 4 + NH 3 54% within a factor of 2 48% within a factor of 2

Spatial interaction of inorganic PM components

Emission reduction scenarios 30% across-the board reduction in SO 2 30% across-the board reduction in NO x 30% across-the board reduction in NH 3 Emission sensitivity coefficient = % change in PM component % change in Emission 1 A 30% reduction in emission gives a 30% reduction in PM component >1 A 30% reduction in emission gives more than a 30% reduction <1 A 30% reduction in emission gives less than a 30% reduction -ve A 30% reduction in emission gives an increase Effects of SO 2 NO X or NH 3 emission reductions.

SE England grid 4x4km resolution Basecase30% less SO 2 30% less NO x 30% less NH 3 PM 2.5 μg m PM fine sulphate mass μg SO 4 m PM fine nitrate mass μg NO 3 m PM fine ammonium μg NH 4 m SO HNO NH Mean μg m -3 Sensitivity coefficient

SE England grid 4x4km resolution Basecase30% less SO 2 30% less NO x 30% less NH 3 PM 2.5 μg m PM fine sulphate mass μg SO 4 m PM fine nitrate mass μg NO 3 m PM fine ammonium μg NH 4 m SO HNO NH Mean μg m -3 Sensitivity coefficient

SE England grid 4x4km resolution Basecase30% less SO2 30% less NOx 30% less NH3 PM 2.5 μg m PM fine sulphate mass μg SO 4 m PM fine nitrate mass μg NO 3 m PM fine ammonium μg NH 4 m SO HNO NH Mean μg m -3 Sensitivity coefficient

Emissions sensitivity coefficient 30% less SO 2 PM μg SO 4 m μg NO 3 m μg NH 4 m SO HNO NH Range Range Range

Emissions sensitivity coefficient 30% less NO x PM μg SO 4 m μg NO 3 m μg NH 4 m SO HNO NH Range Range

Emissions sensitivity coefficient 30% less NH 3 PM μg SO 4 m μg NO 3 m μg NH 4 m SO HNO NH Difference PM 2.5 Range Range Range Range (-)0.75-(-)0.03

Summary Evaluation of the inorganic PM components with observations at Harwell monitoring site. Results are promising but we need to evaluate more sites and both summer and winter. Spatial interaction of inorganic PM components. NO 3 - is poor but this is dependent on NH 3 emissions. Effect of emission reductions of SO 2 NO x NH 3 SO 2 : has a proportional effect on SO 2 but less effect on SO 4 2- NO x : has less effect on HNO 3 and NO 3 - in urban areas. NH 3 : has the most complex effect with -a greater than 30 % reduction in decrease in NH 3 and NO 3 -, -less than 30% reduction in NH 4 + and -an increase in HNO 3

Acknowledgements PhD funding from NCAS-weather UM-MCIP - G Taylor (Aeolus) funded by NCAS EMEP2CMAQ – Armin Aulinger GKSS

Spatial interaction of inorganic PM components