Air concentrations

Air quality measurements are conducted within SWETHRO, Swedish Throughfall Monitoring Nework, at measurement plots throughout Sweden. The monthly measurements include sulfur dioxide, nitrogen dioxide, ammonia, and ozone. Concentrations of air pollutants are measured using diffusion samplers, "passive samplers." This means that the gas is captured on a filter impregnated with a chemical that quantitatively absorbs the gas to be analyzed.

Air concentration measurements are suitable for detecting rapid changes in air quality. This was evident, for example, regarding the impact on sulphur dioxide levels from the volcanic eruption in Iceland in 2014/2015. The impact was first detected through the SWETHRO air measurements in northern Sweden. Additionally, air quality measurements of sulfur dioxide have been used to demonstrate the effect in coastal areas along the Baltic Sea due to reduced sulfur levels in ship fuel.

Measurements of air concentrations in rural environments can, depending on their location, be used both as coordinated recipient control for emissions within the region and to confirm reported reductions in air pollutant emissions across Europe that are transported to Sweden.