ICOS has established a network of tall towers and mountain stations where data on greenhouse gas concentrations in the atmosphere are collected.
Remote stations, for example the ones in the Arctic and the Alps, are located far away from major air pollutants. Information on this kind of clean air provides a basis for long-term changes in greenhouse gases and represents better the changes in the greenhouse gases composition, compared to the more polluted sites. Due to their elevation and the distance to major greenhouse gas sources and sinks, remote stations are mainly exposed to air masses representing background conditions over Central Europe. On the opposite, the stations located within or close to cities are important in understanding urban emissions and further developing the network of urban ICOS stations. These stations play a role in tackling urban pollution and help to verify international greenhouse gas limits.
The data collected at the atmosphere stations are automatically processed and quality controlled by the Atmosphere Thematic Centre. The Central Analytical Laboratories provide calibration gases and analyse samples for additional quality control and to extend the set of observed parameters.