Behavior of Radon in Soil Gas with Changing Meteorological Factors in Northern New Jersey

Radon gas collected from glacial loamy soil in Parsippany, northern New Jersey, showed as much as a 9-fold variation in concentration (from 80 pCi/L to 766 pCi/L). The radon fluctuations coincide with changes in soil moisture and meteorological conditions. The largest variation was observed with change in soil moisture. Radon concentration was lowest when soil moisture diminished (80 - 470 pCi/L) compared with the highest soil radon (264 - 766 pCi/L) which was observed when soil was wet. Extended rain events lasting several days correspond with increase in radon levels which last for up to two weeks (up to 318% increase). Fluctuation in radon levels occurred in all rain events, but the pattern is less consistent during short events. Higher soil moisture corresponded with a larger lag in radon concentration increase following rain events. Patterns in radon change with change in other meteorological conditions were harder to isolate and appeared less uniform. This can be attributed to the complex relationship among meteorological conditions. Wind events reduced soil radon concentration by 12 - 50%. Several events of atmospheric pressure, which were isolated from other factors, showed a strong correlation (0.85) between radon concentration and changes in barometric pressure. These data provide valuable insights into the behavior of radon concentration under different weather conditions and an opportunity to evaluate the dependence of radon and behavior of soil gas on meteorology.