Radon exhalation rate measurement in Amazon Forest soil

Abstract

Measurements of terrestrial residual gas emissions are important for investigations of atmospheric, biological, and geophysical processes. Terrestrial high-frequency flows of the radioactive noble gas ²²²Rn are useful for evaluating the performance of regional atmospheric models through the use of validated radon flux maps. In this sense, this work aims to validate a laboratory method for determining soil parameters that can influence the flow of ²²²Rn in samples collected at the Amazon Tall Tower Observatory (ATTO). Specifically, the pH and humidity values were determined for three soil types. Although more observations are still necessary, we concluded that, in comparison with works reported in the literature, the exhalation rate is in good agreement for tropical forest soils. However, no clear correlation could be observed between the ²²²Rn exhalation rate and soil humidity or pH.