Sammanfattning
The EU directives together with the Swedish environmental legislation will require the Swedish municipalities to assess how they comply with given air quality standards. Model tools will be an important and necessary complement to measurements. Air pollution originates only partly from local sources within a particular municipality and there is often an important part that is transported over long distances, even from outside Sweden. Therefore model tools that aspire to simulate total concentrations of a pollutant, have to involve sources and dispersion on different scales, starting with the entire Europe and going down to the microscale of an individual street.