Air pollution is a problem in Sweden as well as other parts of the globe. SMHI participates in several projects, together with other research institutes, to increase knowledge in connection with the air pollution emissions, health and costs.
Health effects of different particle types
One of the greatest problems concerning air pollution in Europe is the high concentration of particulate matter. The health effect of particles is affected by their properties, such as chemical composition and size. In general particles can be divided into three categories; combustion particles, non-exhaust particles and secondary formed particles.
- Combustion particles derive from the combustion processes such as road traffic and wood combustion. These particles are often ultra fine (less than 0.1 µm). Epidemiological studies have shown that there is a connection between these particles and premature death.
- The greatest contributing factors to the total concentration of particles in traffic environments in Sweden are road, vehicle and tyre wear, primarily as a consequence of the use of studded tyres. These non-exhaust particles are generally larger than 2.5 µm and are known as coarse particles. Much points to the fact that coarse particles cause and worsen illness in breathing organs, but there is uncertainty as to whether or to what extent they cause death.
- Secondary particles are formed in the atmosphere through chemical reactions between other air pollutants (for example nitrogen oxides). It can take a relatively long time for these particles to form, which subsequently means that they are also formed far from the emission area. Secondary formed particles are often less than 2.5 micrometres.
Calculation example of external health costs
Below you can see an example of the estimated external health costs as a consequence of population exposure to particles, from the Swedish research study TESS. The estimations have only included the emissions of particles and particle-forming substances from Greater Stockholm.
|Area||Road traffic||Residential wood combustion||Total (including shipping and energy sector)|