What is the effect of decreased outdoor air entry due to environmental conditions on radon levels?

Decreased outdoor air entry due to environmental conditions leads to higher radon concentrations inside buildings. Radon is a naturally occurring radioactive gas that is primarily produced from the decay of uranium in soil and rock. When outdoor air is able to enter a building, it tends to dilute the concentration of radon that may be present indoors. Factors such as closed windows, low ventilation rates, and atmospheric pressure changes can limit the entry of fresh outdoor air, allowing radon levels to build up inside more readily. In this scenario, the radon that seeps into the building from the surrounding ground has less opportunity to disperse or mix with the outside air, which results in higher indoor concentrations of radon.

The idea of stable radon levels or variable exposure refers to circumstances where the amount of radon does not change significantly or fluctuates, which is less likely in an environment with restricted air exchange. Thus, in situations with decreased outdoor air entry, the likelihood of elevated radon levels increases.