The DAPPLE project: Overview and wind tunnel experiments

1. The DAPPLE project: Overview and wind tunnel experiments Alan Robins1, Paul Hayden1, Janet Barlow2, and the DAPPLE Consortium 1University of Surrey, UK 2University of Reading, UK Home Office CBRN S&T Programme

2. Cities are collections of relatively short streets between intersections - the classical street canyon is a rarity.

3. Dispersion through an intersection What is the impact of the street network on dispersion of and exposure to pollutants? Scaperdas, A (2000), PhD thesis, Imperial College London

4. Dispersion of Air Pollutants and their Penetration into the Local Environment Surrey - project leader, wind tunnel modelling Bristol - tracer studies, analysis Cambridge - tracer studies, modelling & applications Imperial - field site management, exposure, modelling & applications Leeds - traffic movement, emissions, pollution & wind field measurement Reading - meteorology, wind field & modelling Golder Associates (UK) Ltd. (from 2006) - field site management

5. Support and practical outputs In collaboration with TfL, Westminster CC, Camden CC, UK Met Office, HSL, NERI, other UK universities and projects With approval from Met. Police, TfL, Westminster CC, HSE, UK Government Additional support from GLA, APRIL, DEFRA, EA, DSTL (Porton Down), HSE, BRE, NRPB, NSCA, other UK CCs, Din Café & Restaurant. • Strategies to control personal exposure • Guidance on the effectiveness of air quality management strategies; traffic queue and flow control • Education and training material for local authorities and emergency responders

6. Chronology Arnold S et al. (2003) STOTEN Wood C R et al., in press BAMS

7. Routes used in personal exposure study

8. Personal Exposure CO T15 Langan measures carbon monoxide every 10 seconds Casella Ultraflow Pump + Filter measures average PM2.5 concentration for the route Kaur S et al. (2005, 2006) Atmospheric Environment TSI P-Trak measures ultra-fine particles every second Voice and video

9. Field Instrumentation • 7 to 11 sonic anemometers • References on rooftops and at 190m on BT Tower • Automatic Weather Stations, Doppler lidar and Met Office forecasts • CO/NO2 Learian Street Boxes; Instrumented Vehicle; SCOOT (traffic data) • 3 PFC tracer release kits, 18 tracer sampling units • 5 - 25 people on-site (exposure measurement, tracer studies)

10. Wind tunnel flow visualisation

11. Wind tunnel research • EnFlo 20x3.5x1.5 m boundary layer wind tunnel • U = 0 to 3.5 m s-1 ; inlet flow heating; surface heating and cooling mixed basic and detailed 1:200 scale model

12. Flow structure at an intersection Smoke source in Gloucester Place, south of Marylebone Road; wind from the SW. Large Eddy Simulation Carpentieri M et al., submitted Atmospheric Environment

13. Receptor at plume edge Receptor at plume centre Tracer release examples White - ensemble average (~ 100 realisations) Red - single example Simulation of 15 minute release at full scale Field tracer studies yield sets of examples drawn from ensembles in which the mean and standard deviation are of the same magnitude.

14. Dispersion and intersections The basic mean concentration decay function, CUH2/Q = 12 (R/H)-2

15. Summary • DAPPLE project – extensive UK dispersion study in urban area • Short range dispersion (0 – 1km) • 51 full-scale tracer experiments; point and mobile source releases • Detailed wind tunnel and full-scale flow measurements • Intensive fixed and mobile pollution measurements • Fully integrated traffic, pollution, flow and exposure measurements For further information and data queries contact: Project leader Alan Robins a.robins@surrey.ac.uk