A comprehensive literature search and update of the database has been performed, with more data on land use specific concentrations and reduction efficiencies for different types of facilities for many different substances. A comparative study between different land uses and different types of facilities has also been performed, which resulted in some changed values to get reasonable data. Two new rows have been added to the database for each land use, presenting the estimated minimum and maximum concentration used in StormTac Web when changing the “density factor” for a specific land use.
The functions between measured traffic intensities and measured pollutant concentrations have been updated to include all data, with the exception of excluding data of Pb previous to 1995 (Pb-free petrol). Before, the functions were based on only Swedish data from a 10-year period of time since that data resulted in higher fit to the data than if all data are included. These functions are described in the guide in StormTac Web, with references. In the guide, the description of the land use roads has also been updated with description of what kind of traffic intensity (e.g. for both driving directions) should be used for what road area.
The changed standard concentrations and reduction efficiencies have been marked in the database and implemented in StormTac Web. This improves the accuracy of the predictions of pollutant loads.