Radon is an unique atmospheric tracer, and high-quality measurements of direct atmospheric radon concentration complemented by indirect (by progeny) measurements at a key unique location in the Atlantic will open up multiple possibilities for climate science, as well as in terms of radio protection and nuclear surveillance. The radon observations will provide an accurate time-varying baseline reference level for European GHG enabling clearer distinction between emissions and slowly changing background levels. In addition to GHG baseline estimates, the quantification - based on atmospheric radon concentration - of the degree of terrestrial influence on air masses will significantly assist multiple atmospheric and multidisciplinary environmental studies. These will be addressed in the project, including the quantification of pollution events, the investigation of the feedback of natural planktonic communities occurring at the surface North Atlantic to GHG emissions, and atmospheric studies of marine boundary layer clouds and aerosols. The project will also increase understanding on wet deposition and meteorological processes influencing ambient gamma dose rate that need to be taken into account in setting threshold alarm levels of nuclear surveillance networks for radiological protection purposes.