Radon detector. This device is used to detect and measure levels of radon gas in homes. The radon causes damage to a piece of plastic in the detector, which is proportional to the amount of radon present in the air. Radon is a radioactive gas produced by the decay of small amounts of uranium found naturally in all rocks and soil. Levels of radon differ with different geological conditions. In areas with high levels it needs to be prevented from accumulating inside buildings. Exposure to radon increases the risk of developing lung cancer.