Air Dispersion Modelling
Plume Impacts on Aviation Safety
Environmental Noise and Vibration Assessments
Emission Estimation and Emissions Inventories
Environmental Management Services
Environmental Toxicology, Pathology and Public Health
Air dispersion modelling represents the most effective means of predicting air pollution impacts associated with regional, local and/or specific industry emissions at locations surrounding the source. Dispersion modelling is a specified requirement of virtually all environmental authorities for licensing compliance and development approval applications. In addition to assessment of the spatial extent of pollutant concentrations and compliance with regulatory limits/guidelines, the pollutant concentrations calculated by the model may be used to assess important operational aspects such as the relative contribution of individual sources, the effects of important release parameters such as stack height, temperature and velocity, as well as management options such as changes to operating hours or equipment operation.
Air dispersion modeling has several advantages over ambient air monitoring, including:
- Ability to predict impacts of proposed developments and equipment or process changes prior to implementation or construction
- Ability to predict impacts at every location within the entire local region
- Ability to determine pollution impacts of the specific sources of concern
- Ability to account for all relevant atmospheric conditions to produce statistically significant results including time averaging statistics suitable for comparison with local authority air quality goals.
In every-day industrial situations, atmospheric dispersion modelling is a very cost-effective tool for performance improvement and avoidance of costly pollution events due to process changes and expansions. For example common industrial applications include:
- Stack height and stack location optimisation
- Optimisation of treatment plant costs by determining the relative contribution of individual sources where multiple sources are present
- Assessment of management controls needed to minimize nuisance impacts due to releases such as odour and/or dust
- Assessment of the effects of proposed future changes to plant and equipment for optimisation of plant layout and capital expenditure
- Assessment of off-site impacts and understanding of future issues such as urban encroachment, health impacts and potential exposure to litigation
- Risk analysis and emergency planning
Mirrabooka Consulting has extensive experience in the application of air dispersion codes including the most recent 3-dimensional codes, TAPM and CALPUFF, to a variety of industrial and regional activities. Dr Scholz has also developed photochemistry codes which integrate with the Gaussian Plume models such as AUSPLUME and Industrial Source Complex 3 (ISC3).
TAPM (developed by CSIRO) is a world class meteorological and air dispersion model. Its air dispersion module is unique in that it evaluates its own 3-dimensional meteorological dataset using the fundamental equations of the atmosphere in combination with a meteorological database that spans the entirety of the region under study. The dispersion algorithms take into account full 3-dimensional influences of the atmosphere including plume history (and hence recirculation), turbulence, drainage flows and the development of internal boundary layers in coastal regions. The meteorological data generated by TAPM can also be used as input into a variety of other air dispersion models such as Calpuff, AUSPLUME and ISC3.
CALPUFF was developed by the US EPA and is the most sophisticated air dispersion model available in the US. In common with TAPM, it takes into account the full 3-dimensional variation of the atmospheric parameters. However it is unable to generate its own meteorological data and so is dependent upon observations from meteorological stations or on data generated by TAPM or other meteorological modeling programs.
Certain air quality assessments do not require the implementation of 3-dimensional models. Gaussian models such as the US EPA’s ISC3 or Australia’s AUSPLUME are often adequate for regions with relatively simple terrain and meteorological influences. In these instances regulatory authorities accept that the application of these simpler models is sufficient for licensing compliance and development applications.
Mirrabooka Consulting’s expertise in air dispersion modelling extends beyond simply running models. Our staff have a thorough understanding of the limitations of each model and the experience to select the most appropriate model for each individual situation. Mirrabooka Consulting is therefore better placed than many of its competitors to advise on model selection, suitability and application.
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