The DAPPLE project:

Overview and wind tunnel experimentsAlan Robins1, Paul Hayden1, Janet Barlow2,

and the DAPPLE Consortium

Home Office

CBRN S&T Programme

2University of Reading, UK

1University of Surrey, UK

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

Dispersion through an intersection

Scaperdas, A (2000), PhD thesis, Imperial College London

What is the impact of the street network on dispersion of and exposure to pollutants?

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

Support and practical outputs

Additional support from GLA, APRIL, DEFRA, EA, DSTL (Porton Down), HSE, BRE, NRPB, NSCA, other UK CCs, Din Café & Restaurant.

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

• 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

Chronology

2002 EPSRC-DAPPLE start

2003 Spring field work

2004 Spring and Autumn field work

2005 Analysis, workshops, dissemination

2006 EPSRC-DAPPLE endDAPPLE-HO start

2007 Spring/Summer field work

20082009

Winter/Spring 07/08 field workData release by Home Office end 2009

Arnold S et al. (2003) STOTEN

Wood C R et al., in press BAMS

Routes used in personal exposure

study

CO T15 Langan measures carbon monoxide every 10 seconds

TSI P-Trak measures ultra-fine particles every second

Casella Ultraflow Pump + Filter measures average PM2.5 concentration for the route

Personal Exposure

Voice and video

Kaur S et al. (2005, 2006) Atmospheric Environment

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)

Wind tunnel flow visualisation

Wind tunnel research

mixed basic and detailed 1:200 scale

model

• EnFlo 20x3.5x1.5 m boundary layer wind tunnel

• U = 0 to 3.5 m s-1 ; inlet flow heating; surface heating and cooling

Large Eddy Simulation

Flow structure at an intersection

Smoke source in Gloucester Place, south of Marylebone Road; wind from the SW.

Carpentieri M et al., submitted Atmospheric Environment

Tracer release examples

Field tracer studies yield sets of examples drawn from ensembles in which the mean and standard deviation are of the same magnitude.

Receptor at plume centre

Receptor at plume edge

White - ensemble average (~ 100 realisations)

Red - single example

Simulation of 15 minute release at full

scale

Dispersion and intersections

The basic mean concentration decay function, CUH2/Q = 12 (R/H)-2

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