1. THE REGENTS PARK AND TOWER ENVIRONMENTAL EXPERIMENT REPARTEE 2006 & 2007 Roy M. Harrison University of Birmingham

2. PARTICIPANTS IN REPARTEE InstitutionRole University of BirminghamProject management Soluble ions ATOFMS NO, NO 2, O 3, SMPS University of ManchesterAerosol fluxes HR-AMS Centre for Ecology & Hydrology,Particle fluxes Edinburgh & Lancaster UniversityGas fluxes (PTR-MS) Particle and gas chemistry AMS Kings College, LondonElectron microscopy of particles University of CambridgeNO 3 and N 2 O 5 measurement University of Reading &Meteorological measurements including University of SalfordDoppler Lidar University of BristolField dispersion of inert tracer

3. REPARTEE OBJECTIVES OF REPARTEE To study aerosol chemical and dynamical processes within the atmosphere of central London in three spatial dimensions. To measure the fluxes of selected aerosol and gas phase species above the city, and where possible to compare fluxes with estimates derived from emissions inventories. In this context, the work was coordinated with that on the CityFlux project in which fluxes were determined over a number of UK cities. To quantify gradients in selected aerosol and trace gas species from ground-level to altitudes of sampling on the BT tower and to use such information to better understand the respective roles of local emissions, local transformations and regional transport of pollutants in influencing the composition within and above London.

4. REPARTEE OBJECTIVES OF REPARTEE – cont’d To study the structure of the atmospheric boundary layer and the influence of boundary layer vertical structure upon trace gas and aerosol fluxes and air pollution processes. To deploy purposeful tracer releases at ground level while monitoring at the surface and aloft in order to evaluate the dispersion of trace gases released at low level within the city. To determine spatial differences in aerosol particle size distributions and to interpret those differences in terms of the sources and physico-chemical transformations responsible. To study the properties of nitrate aerosol in the atmosphere of London, together with mechanisms of formation, physico-chemical properties and dynamics of nitrate particles. To throw new light on the source apportionment of PM 1, PM 2.5 and PM 10 in the atmosphere of London.

5. THE SAMPLING SITES

6. Map of Central London

7. Meteorological instruments and fast response pollution sensors Height of most instruments BT TOWER

8. REGENTS PARK FROM THE TOWER

9. MARYLEBONE ROAD

10. NORTH KENSINGTON

11. Universities Facilities for Atmospheric Measurement (UFAM) 1.5 micron scanning Doppler lidar (Halo-photonics) 24 th Oct to 14 th Nov 2007 vertical stare 30 m resolution gates integration every 4 sec backscatter along beam Doppler velocity (vertical component) Doppler Lidar Measurements

12. Mass and Major Component Chemical Data

13. REPARTEE DATES REPARTEE I27 Sept-23 Oct 2006 REPARTEE II16 Oct – 11 Nov 2007 Air masses during REPARTEE I Mainly maritime, except 11-12 Oct : arrives over France 14-17 Oct : from Poland over near continent

16. DATA FROM THE AEROSOL TIME-OF-FLIGHT MASS SPECTROMETER AND AEROSOL MASS SPECTROMETER

17. Time series of AMS nitrate and ATOFMS nitrate particle count, London, 2006

18. Time series of two nitrate particle types, London, 2006

19. Mass spectra of two nitrate particle types measured in London, 2006

20. Time series demonstrating the semi-volatility of type 2 nitrate

21. Particle Size Distributions – SMPS data

23. Conclusions The experiments have proved powerful in identifying spatial patterns in pollutant concentrations and size distributions, and in elucidating atmospheric physico- chemical processes. Work on vertical gradients has been especially informative. Particle size distributions are highly dynamic and site- dependent. There are many other aspects to the experiment which my colleagues will report upon.

24. ACKNOWLEDGEMENTS Funding:  National Environment Research Council and the BOC Foundation. Science Contributions:  Dr Manuel Dall’Osto  Mr Alistair Thorpe  Dr David Beddows  Numerous collaborators from other institutes