Dispersion of Air Pollution & Penetration into the Local Environment

Reports and conclusions

The final report to EPSRC can be seen here and the associated summary reports from each university here.


A list of project publications and conference presentations can be seen here.


The EPSRC Dapple project has created a number of very comprehensive data-sets, as summarised below. Contacts for each are also given.

Wind tunnel data:

Approach flow conditions; LDA velocity and turbulence field; fast FID mean and fluctuating concentration fields; slow FID mean concentration fields; LDA-FFID mean and turbulence fluxes. Contact Paul Hayden at: p.hayden@surrey.ac.uk

Meteorological data:

BT Tower, roof top and in-street ultrasonic anemometer data; background meteorological data. Contacts Janet Barlow at: j.f.barlow@reading.ac.uk or Alison Tomlin at: fueast@leeds.ac.uk

Traffic and ambient pollution data:

Traffic flows and emissions data; instrumented car data; air quality data. Contact James Tate at: j.e.tate@its.leeds.ac.uk or Margaret Bell at: M.C.Bell@ newcastle.ac.uk

Exposure data:

Personal exposure data and related exposure and ambient air quality data. Contact Helen ApSimon at: h.apsimon@imperial.ac.uk

Tracer dispersion data:

Tracer concentrations for each field tracer experiment and related meteorological data. Contact Dudley Shallcross at: D.E.Shallcross@bristol.ac.uk

Publications and Presentations

We intend to make a selection of DAPPLE related publications and presentations available shortly.


Welcome to our downloads section. Most material is supplied as PDF files requiring the use of Adobe Acrobat Reader or similar pdf viewer.


  1. The current version of the DAPPLE tri-fold leaflet is available here (244kB)


  1. Thanks are due to various consortium members and Dominic Edsall for the photos throughout the site
  2. An album of general photos is available here


  1. A summary of the DAPPLE project was published in the September 2008 issue of the HPA Chemical Hazards and Poisons Report (Issue 13, pages 24-28). The full report can be obtained here.
  2. An initial note is available here (376kB) describing nominal 10 second "puff" releases performed in the EnFlo wind tunnel at UniS.
  3. An analysis of predicted full-scale concentration fluctuations deduced from wind tunnel measurements is available here (92kB).
  4. A note entitled "Decay of Maximum Concentration in an Urban Area" is available here (720kB).
  5. A note entitled "Flow visualisation studies - 1" is available here (464kB); associated video material can be viewed from the Video section below.
  6. A note entitled "Effects of blockage on dispersion in urban canyons" is available here (968kB).
  7. A note entitled "EnFlo Ground Level Concentration Data and the Inverse Square Decay Law" is available here (1.2MB).
  8. A note entitled "Wind tunnel simulation of short-range dispersion in an urban area" is available here (1.6MB).
  9. A first report (168kB) from Cambridge, entitled "A simple correlation for pollution dispersion prediction in urban areas" summarises the work undertaken in the design of the first DAPPLE tracer experiment.
  10. A second report (468kB) from Cambridge on computational modelling is entitled "Comparison of a simple correlation for pollution dispersion prediction in urban areas with results from the DAPPLE tracer field experiment".
  11. A third report (520kB) from Cambridge on computational modelling, entitled "Comparison Of Predictions From The Baseline Urban Dispersion Model With DAPPLE Tracer Field Experiments" is now available.
  12. A fourth report (860kB) from Cambridge on computational modelling is entitled "Comparison of Predictions from the ASUDM with the DAPPLE tracer field experiment".
  13. The Final Reports (13MB) from the DAPPLE projects as a single pdf file.
Comments or questions can be directed to the authors via info@dapple.org.uk


These videos support the flow visualisation report, Number 4 above.

Link to a video (mp4, 3.7MB) of the three dimensional structure of flow exchanges at an intersection; the wind is at 45 degrees to the street system. Smoke visualisation in the EnFlo wind tunnel: Intersection flows
Link to a video (mp4, 0.6MB) of flow exchanges ("switching") in a horizontal plane at an intersection; again, the wind is at 45 degrees to the street system. Smoke visualisation in the EnFlo wind tunnel: Flow switching
Link to a video (mp4, 0.9MB) of concentration traces for individual short releases of a tracer gas in the wind tunnel. The first set of 15 were measured in the centre of the tracer cloud and the remaining 16 near its edge. The white lines are the averages from about 100 such releases and the red the individual results. The instrument has a frequency response of about 200Hz and 1 second of wind tunnel time is approximately 1 minute at full scale. Wind tunnel Concentration traces