DAPPLE (Dispersion of Air Pollution & Penetration into the Local Environment)

Image removed.The DAPPLE projects ran from 2002 to 2010 and brought together multidisciplinary expertise from six universities capable of undertaking urban fieldwork (Marylebone Road field site), wind tunnel and computational simulations in order to provide a better understanding of the physical processes affecting street and neighbourhood scale air flow and pollutant or contaminant dispersion, with a particular emphasis on individual exposure and source-receptor relationships.

In all, DAPPLE ran for nine years and clearly established the team involved as the only group in the UK experienced in conducting large-scale urban dispersion experiments. The projects were led by Professor Robins at the University of Surrey.

DAPPLE was EPSRC funded from 2002 to 2006 and concentrated on traffic pollutants. Home Office funding then followed from 2006 to 2010, when the emphasis shifted from the earlier concerns to the short range dispersion of hazardous, gaseous material, primarily addressing potential terrorist activities in London or similar urban conditions.


The TSB-EPSRC funded project, DYCE (2009-2010) built on the success of DAPPLE, but moved to address inverse modelling for source identification in open and urban environments. The work concentrated on the role of data quality on the uncertainty attached to outputs from the inversion process. An associated activity was to demonstrate the performance of new mobile monitors for detecting and identifying chemical agents. The lead organisation was Selex-Galileo.


MODITIC is an EDA project that runs from 2012 to 2015 and is led by the Norwegian Defence Research Institute. It treats the hazards associated with toxic industrial chemicals (e.g. chlorine, ammonia etc.) that are produced, transported and stored in relatively large quantities.

The consequences of accidental or intentional (operational or malicious) release of such compounds are of concern both to military and civilian authorities. The objective is to conduct a systematic study of the release and airborne dispersion of relevant chemicals in complex urban environments for a range of atmospheric conditions, to enhance our understanding of the processes involved and thus support improvements in modelling and backtracking techniques.

The novelty of the project is the focus on European style topographies and urban characteristics, in combination with negatively buoyant emissions and non-neutral atmospheric conditions. The project will perform numerical simulations, wind tunnel dispersion experiments, related source term experiments and computations for releases from pressurised vessels.


The EPSRC funded DIPLOS project commenced in 2014 and runs for three years. It is led from Reading (Meteorology) and treats the street network dispersion modelling concept initially developed at ECL (France).

The intention is to use wind tunnel experimentation together with DNS and LES computational modelling to look closely at the underlying physics of dispersion in street networks and its relation to the basic assumptions of the street network modelling concept.


EnFlo is a member of the APRIL network (Air Pollutions Research in London) and contributes to a number of network activities. Recent interest has focussed on the dispersion of exposure to fine particles and the dispersion of roof top emissions (typically from small scale CHP plant) in London.


A parallel theme of research developed around off-shore wind power, within the EPSRC funded SuperGen consortium, 2006-2014. This work concentrates on the structure and development of wind turbine wakes and the interaction between wakes and machines in large off-shore arrays.

It research utilises stable, neutral and unstable off-shore boundary layers, establishing satisfactory simulations that widened the range of ‘standard’ flow conditions available in the EnFlo wind tunnel.

Nano-particle dispersion

The theme of nano-particle dispersion in the atmosphere has established a new area of EnFlo research, in collaboration with colleagues in Civil Engineering. The initial focus has been vehicle pollution, in particular processes that determine particle dispersion in vehicle wakes.

This was the first project to utilise the new rolling road capability of the ‘Aero’ wind tunnel, a facility developed under SRIF 4 funding.


A series of projects for the HPA (now PHE) has been completed within the EngD programme. The first two covered health and related aspects of waste management and the third odour, including an unusual example of long range odour transport (from Germany to the UK).

Current work is with Guys and St Thomas’ Hospital and treats the physics of short range dispersion from short, roof top stacks; the case study being emissions from the cyclotron facility at St Thomas’.


CONCAWE is based in Brussels and commissions environmental research on behalf of its members (mainly petrol-chemical industries). Projects at EnFlo have focussed on near-field dispersion at process plants and, in particular, the use of line integrated concentration measurements around a plant to estimate emission rates of hydrocarbons from leaks and similar sources.

The overall aim is to understand the uncertainties in the resulting estimates and to develop best practice for carrying out such work.

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