Inverse modeling of Asian 222Rn flux using surface air 222Rn concentration

► Annual 222Rn flux density for Asia was estimated to be 33.0 mBq m−2 s−1 by using atmospheric 222Rn concentrations with Bayesian synthesis inverse method. ► Estimated 222Rn flux densities decrease with increasing latitude. ► Estimated 222Rn flux densities are robust against uncertainties of assumption of Bayesian synthesis inverse method.