Scenario tool - visualization and evaluation of emission scenarios

Development of the model system SIMAIR is currently being carried out with the aim of highlighting and visualising the differences and consequences of different emission scenarios.

A comprehensive decision support system aimed at researching the consequences of measures and emission scenarios within different sectors of society, such as energy production and road traffic, is currently lacking in Sweden. It is from this background that SMHI is currently developing a Scenario tool, with the idea of filling the knowledge gaps within the area.

Within a period of two years, the project will result in the tool, being used for the evaluation of air pollution, population exposure, health effects and external health costs.

Current questions

The objective is for the aspects, which refer to efforts pertaining to environment and health effects, to be studied with the new Scenario tool. The decision-makers can then research the measures to be taken in each scenario and these can be tested through model simulation so that the effects of the measures can be assessed from environmental, health and economic perspectives.

Examples of current questions that can be analysed are health and economic benefits that can be achieved through:

  • all old wood stoves are replaced with new ones
  • changes in energy consumption, for example increased use of bio fuel
  • decrease in the use of studded tyres in certain parts of the country by a certain amount
  • a change in transport policy, from road transport to rail and sea
  • reduction in emissions from certain source by a certain amount
  • changed metrological conditions
  • changes in physical planning


The module will contain functions that highlight and visualise the differences between the various concentration fields.

The methods of calculation can be clearly described in the following manner. The question to be analysed is first defined. The concentration field is presented in part to create a Base case and partially for a Scenario case. The Base case can correspond to the current situation or, for example, a scenario for a certain year where an emission development has been assumed to have occurred without any change of policy ("business as usual"). The Scenario case corresponds to the calculated concentration for the political or technical changes that are to be studied.

For each case, calculations are made with a dispersion model where emission data is customised to the question. In the Scenario tool the differences are calculated between the Base case and the Scenario case and a new concentration is created thereby describing the changes in the Air Quality. Thereafter, the changes in exposure are calculated based on detailed population data for the entire country and the health effects of this change as well as the economic value of the changed health effects.

Schematic sketch of the Scenario tool.
A schematic sketch of the calculation methods for the Scenario tool. Based on the changes in emission as a result of a political or technical measure, reduction/increase of the concentration of air pollution can be studied. With knowledge of the population within these areas the exposure can then be calculated. Thereafter, with the help of the connection between the exposure and health the health benefits/losses can be assessed, together with an estimation of the reduction/increase as a result of this measure.
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Project in cooperation

The project is a cooperation between SMHI, Swedish Environmental Protection Agency, Swedish Road Administration, Swedish Energy Agency, Umeå University and Swedish National Road and Transport Research Institute.