Matorova station, Finland. Matorova station. Instruments on roof showing POP sampler, above the lamp the inlet of the radon monitor, a housing for the air conductivity meter and inlet filters for the aerosol samplers. Analyses include inorganic ions; trace metals, mercury and persistent organic pollutants (POP). Part of a global programme for monitoring and assessing chemical composition and related physical characteristics of the global background atmosphere. The station is maintained by the Finnish Meteorological Institute (FMI) and the Finnish Forest Research Institute (METLA).