Dispersion Monitoring

Cti offers an air dispersion modelling service using the latest ADMS software.

Historically Cti has used ADMS software for many years, and has extensive experience of undertaking dispersion modelling to assess pollutants and odour concentrations against ambient air health and nuisance benchmarks at small and large sites in the UK.

Air dispersion modelling is used to predict ground level pollutant concentrations in an area around the source(s).  The results are often presented as concentration contour plots, which can be used to identify areas of unacceptable impact.

Modelling is more expensive than simple stack height calculations and H1 assessments, but becomes a very cost-effective approach in the following circumstances:

  • Where simple calculations result in excessively high stack heights that would be expensive to install.
  • Where multiple discharges from stacks and vents are present.
  • Where a better understanding of the impact of discharges is required, e.g. if the company is located near a site of special scientific interest.
  • Where management controls are needed to minimise odour impact.  The model determines the conditions under which odour complaints are likely to occur, which can be used to plan a mitigation strategy.
  • Where the impact of changes in emissions, emission controls or stack heights are being assessed.  Potential changes can be input into the model to see the effect on the dispersion pattern.

The model is site specific.  Input data includes stack measurement details from the site, current stack and building heights, local meteorological data and corrections for local topography and adjacent buildings.

To discuss this service, please contact Trevor Halliday on t.halliday@castingstechnology.com or 07787500063

Sometimes, the Environment Agency’s IPPC HI software (Guidance Note: Environmental Assessment and Approval of BAT) can be used initially to determine whether detailed dispersion modelling is merited.

Cti can also perform simple chimney height calculations in accordance with HMIP Technical Guidance Note D1 (Dispersion): Guidelines on Discharge Stack Heights for Polluting Emissions.