Estimation of soil Rn-222 exhalation rate and its dependence on meteorological parameters in Purulia District, West Bengal, India

The present study deals with the observation of Rn-222 emanation process in terms of its exhalation rate for 48 h from sub-surface soil at 3 h intervals, using a continuous Rn-222 monitoring system RAD7 at Sidho-Kanho-Birsha University campus in Purulia district, located in the easternmost part of the Chotanagpur Plateau, India based on local weather conditions, over five different seasons. For every season, the diurnal variations of the Rn-222 exhalation rate increase after sunset, reaching to its maximum at mid-night and thereafter starts decreasing until it falls to the minimum around noon time. Local meteorological parameters such as ambient temperature, relative humidity, atmospheric pressure were also recorded during the observation period to study the possible influences of these parameters on the soil gas Rn-222 emission rates using Pearson's correlation matrix. There exists a strong positive correlation between relative humidity and Rn-222 exhalation rate and a positive correlation between atmospheric pressure and Rn-222 exhalation rate for all the observation periods. On the other hand, negative correlations between the atmospheric temperature and the Rn-222 exhalation rate exist for all the seasons. (author)