How much heavier is radon gas compared to air?

Radon gas is approximately seven times heavier than air, which is why the choice indicating this is the correct answer. This significant difference in density is important in the context of radon measurement and mitigation, as radon, being a heavier gas, tends to accumulate in lower areas of buildings, especially in basements and crawl spaces. Understanding the relative weight of radon compared to air is crucial for professionals dealing with radon measurement and mitigation to ensure effective strategies are employed for reducing radon concentrations in indoor environments. This knowledge informs the placement of radon detectors and the design of mitigation systems to address accumulation where radon is most likely to occur.