Air Pollution Assessment Studies for Sweden Based on the Match Model and Air Pollution Measurements

Abstract

The MATCH (Mesoscale Atmospheric Transport and CHemistry) model has been developed as a tool for air pollution assessment studies on different geographical scales. Model versions covering Europe, Sweden and subregions of Sweden have been used as a basis for decision making concerning environmental protection in Sweden. MATCH is an Eulerian atmospheric dispersion model, including physical and chemical processes governing sources, atmospheric transport and sinks of oxidized sulfur and oxidized and reduced nitrogen. With the MATCH system, air pollution contributions from different source types like traffic, industry, shipping, farming etc. can be obtained. Using a combination of air and precipitation chemistry measurements and the MATCH model, the contribution of air pollution and deposition from long-range transport can be quantified in the model region. Also hourly mappings of ozone concentrations are obtained. The calculations for the year 1991 show that the Swedish import was about 4.5 times larger than the export for sulfur and about six times larger for reduced nitrogen, while the Swedish import of oxidized nitrogen only exceeded the export by 10%. Using the MATCH system we estimate the long-range transport in an independent way compared to EMEP. Comparison between the EMEP and MATCH calculations for 1991 show that the total deposition of oxidized nitrogen over Sweden is similar, while the EMEP-values for total deposition of oxidized sulfur and reduced nitrogen are 25% respectively 40% smaller than what is obtained from MATCH. The Swedish contributions to deposition over Sweden are also somewhat smaller (20–38%) in the EMEP model compared to MATCH. Results from MATCH for the year 1994 show a decrease in sulfur deposition over most of Sweden, both from Swedish sources and long-range transport, except for south-east Sweden where a pronounced increase in long-range transport contribution was obtained.