True or False: Leaky return ducts can increase indoor Radon concentration when the furnace blower is on.

Leaky return ducts can indeed increase indoor radon concentration when the furnace blower is on because they create a negative pressure zone within the building. When the blower operates, it pulls air from the return ducts into the heating system, which can inadvertently draw air from soil or other areas that contain radon. This can occur especially in homes with basements or crawl spaces where radon is likely to accumulate. Consequently, when air from these areas is introduced into the indoor environment, the levels of radon can rise, posing a health risk.

In essence, the presence and condition of the ductwork, alongside the operation of the furnace blower, play a significant role in the movement of radon-laden air into living spaces. This scenario highlights the importance of both proper ventilation and the maintenance of duct systems to mitigate radon exposure in homes.