WHO不久前告诫说,北半球的家居业主和建筑物管理人员应采取措施改善室内空气流通,尤其在每年的冬季比以往任何时候都要注意,以便降低家居的氡水平。家居和其他建筑物中放射性氡气的最高水平发生在冬季,这是因为冬季窗户通常保持关闭甚至密封,这会困住通过建筑物地基的小裂缝渗入的氡气。这些建筑物的居住者和使用者暴露于氡气, WHO warned not long ago that homeowners and building managers in the northern hemisphere should take steps to improve indoor air circulation, and pay more attention to it every winter than ever in order to reduce radon levels in homes. The highest levels of radon in homes and other buildings occur in winter, as windows in winter usually remain closed or even sealed, which can trap radon entering through small cracks in the foundation of a building. Residents and users of these buildings are exposed to radon,