“…Gaseous radon and thoron ( 220 Rn from thorium decay series) in soil exhibit similar exhalation responses to environmental factors. , For instance, soil temperature positively affects their exhalation rates. ,− Additionally, their exhalation rates increase with rising soil water content up to a certain level, beyond which they gradually decrease with further increases in soil moisture. − Therefore, aerosol data of thoron’s progeny 212 Pb can be used to infer radon gas concentration variations in soil/atmosphere. Moreover, studies have shown that soil water content is the primary factor affecting their concentrations. , So the 212 Pb data also reflect changes in SAWC conditions within the topsoil layer of a few centimeters, where thoron primarily originates.…”