Modelling of dispersion of different substances or pollutants in the atmosphere is an important part of the Air Quality Assessment (AQA) and Air Quality Management (AQM) processes.

Dispersion modeling is one of the components of the assessment cycle, the other two being monitoring and emissions.

Dispersion modeling – general information

AQA and AQM have traditionally been based on measurements of ambient air quality. Networks of measurement stations are used for collecting data for analysis of the air pollution in urban areas and on larger scales.

Measurements in combination with modelling

The ultimate purpose of assessment is not to collect data, but to provide information necessary for scientists, policy-makers and planners to make informed decisions on managing and improving the environment. Ambient air quality measurement has a central role in this process, but it needs to be used in conjunction with other, complementary, objective techniques like:

  • Air quality dispersion modelling
  • Emission inventories
  • Emission measurements

Generally speaking dispersion modelling, especially after the initial work to obtain data has been done, is less costly than measurements.

Important inputs

Emissions data from a variety of sources are important input data for dispersion modelling. Necessary input data for models are also phsyiographical data as land-use information, topographical (terrain) data and, not least, meteorological data.

Dispersion modelling in Airviro

The Dispersion module in Airviro is a framework for integration of dispersion models into the Airviro environment.

Optimized work flow

Dispersion optimizes the workflow when performing dispersion simulations. Time-consuming work connected to preparation of input data, controlling model runs and post-processing of results is minimized.

Presentation of results

Results are stored in a high performance database, making even very large amounts of data readily accessible. Presentation of dispersion results can be made rapidly using built-in tools or using external GIS software.

Effective and easy to use

The Dispersion framework can have tailor made menus for input to the different dispersion models, making highly advanced models available also to non-expert users.

Using modern technology to optimize computational performance, Dispersion can be used for demanding computations such as hour-by-hour simulations over long time periods, real-time modelling or forecasting.

Different application types

  • Optimizing of monitoring network
  • Interpretation of monitoring data
  • Interpolation of monitoring data
  • Estimation of air pollution contributions from specific sources
  • Estimation of long range transport of air pollution
  • Evaluation of the quality of emission data bases
  • To establish emission control legislation; i. e. determining the maximum allowable emission rates that will meet fixed air quality standard
  • Evaluate proposed emission control techniques and strategies; i. e. evaluate the impacts of future control and emission reduction plans
  • Select locations of future sources of pollutants in order to minimise their environmental impacts
  • Planning the control of air pollution episodes; i. e. defining immediate intervention strategies, (i. e. warning systems and real time short term emission reduction strategies) to avoid severe air pollution episodes in a certain region
  • Assessing responsibility for existing air pollution levels; i. e. evaluating present source - receptor relationships