Radon gas levels are most effectively lowered in buildings with basement or slab-on-grade foundations by active subslab suction, reports the Environmental Protection Agency. Radon levels in buildings with crawlspaces are effectively reduced by submembrane suction. Other techniques include sealing foundation cracks, room pressurization, and natural and artificial ventilation.
Active subslab suction clears radon from the soil beneath a building by means of suction pipes inserted through the floor or beneath the foundation slab, states the EPA. Drain-tile suction, sump-hole suction and block wall suction are similar techniques to direct radon away from building foundations. Submembrane suction involves the installation of a plastic sheet over the ground beneath a building, and a vent pipe draws the radon from the soil.
Although sealing foundation cracks often accompanies other radon reduction techniques, it is not sufficiently effective in reducing radon levels by itself, cautions the EPA. Room pressurization uses a fan to increase air pressure in lower rooms to inhibit radon intrusion, but it is not as effective as suction techniques and sometimes supplements other methods. A heat recovery ventilator lowers radon levels by increasing ventilation. Natural ventilation decreases radon, but when doors and windows are closed again, the amount of radon in the building returns to pre-ventilation levels within 12 hours.
Radon is the second leading cause of lung cancer in the United States, according to the American Cancer Society. Most people are exposed by inhaling it, especially in basement and ground-level rooms in homes, schools and commercial buildings.