Which of the following is NOT a way to reduce radon levels in homes?

Using air purifiers is not an effective method for reducing radon levels in homes. Air purifiers are designed to remove airborne particulates and contaminants, such as dust and pollen, but they do not address the primary concern of radon, which is a radioactive gas released from soil and radioactive materials in the ground. Radon typically enters homes through cracks in floors, walls, and construction joints, as well as through building materials and water supply.

In contrast, the other methods listed—such as increasing ventilation, sealing cracks in floors, and installing radon mitigation systems—specifically target the reduction of radon gas accumulation within living spaces. Increasing ventilation helps dilute radon levels by introducing fresh air, while sealing cracks in floors helps prevent radon from entering. Installing radon mitigation systems is often the most effective solution, as it can involve the use of fans and piping to actively reduce radon concentrations. Understanding these methods is crucial for effective radon management in residential environments.