The document presents an analytical approach to estimate the range of alpha particles emitted from radon gas. It discusses the stopping power and range of charged particles as they pass through matter. Equations from Bohr and Bethe are provided to calculate stopping power. The results of simulations using SRIM2013 software to calculate alpha particle range and detection probabilities in air are presented and compared to previous SRIM versions. Tables and figures show trends in stopping power and range as alpha energy increases.