Brill A B, Becker D V, Donahoe K, Goldsmith S J, Greenspan B, Kase K, Royal H, Silberstein E B, Webster E W
University of Massachusetts Medical Center, Worcester 01655.
J Nucl Med. 1994 Feb;35(2):368-85.
The risk from environmental radon levels is not higher now than in the past, when residential exposures were not considered to be a significant health hazard. The majority of the radon dose is not from radon itself, but from short-lived alpha-emitting radon daughters, most notably 218Po(T1/2 3 min) and 214Po (T1/2 0.164 msec) along with beta particles from 214Bi (T1/2 19.7 min). Radon gas can penetrate homes from many sources and in various fashions. Measuring radon in homes is simple and relatively inexpensive and may be accomplished in a variety of ways. Although it is not possible to radon-proof a house, it is possible to reduce the level. In high radon areas, if the average level is higher than 4-8 pCi/liter (NCRP recommended level is 8 pCi/liter; EPA recommended level is 4 pCi/liter), appropriate action is advised. The shape of the dose response curves for miners exposed to alpha-emitting particles in the workplace is consistent with current biologic knowledge. It is linear in the low dose range and saturates in the high dose range. No detectable increase in lung cancer frequency is seen in the lowest exposed miners (those with exposures < 120 WLM, the relevant dose interval for most homes). Evidence for a health effect from radon exposure is based on data from animal studies and epidemiologic studies of mines. Extensive radiobiologic data predict a linear dose-response curve in the low dose region due to poor biological repair mechanisms for the high density of ionizing events that alpha particles create. However, no compelling evidence for increased cancer risks has yet been demonstrated from "acceptable" levels (< 4-8 pCi/liter).
现在环境中氡水平带来的风险并不比过去更高，过去人们并不认为住宅中的氡暴露会对健康构成重大危害。大部分氡剂量并非来自氡本身，而是来自短寿命的发射阿尔法粒子的氡子体，最显著的是218钋（半衰期3分钟）和214钋（半衰期0.164毫秒），以及来自214铋（半衰期19.7分钟）的贝塔粒子。氡气可以通过多种来源、以各种方式渗透到房屋中。测量家庭中的氡很简单且成本相对较低，可以通过多种方式完成。虽然不可能使房屋完全防氡，但降低氡水平是可行的。在高氡地区，如果平均水平高于4 - 8皮居里/升（美国国家辐射防护与测量委员会推荐水平为8皮居里/升；美国环境保护局推荐水平为4皮居里/升），建议采取适当行动。工作场所中接触发射阿尔法粒子的矿工的剂量反应曲线形状与当前生物学知识一致。在低剂量范围内呈线性，在高剂量范围内达到饱和。在暴露水平最低的矿工（暴露量<120工作水平月，这是大多数家庭的相关剂量区间）中，未观察到肺癌发生率有可检测到的增加。氡暴露对健康有影响的证据基于动物研究和矿井流行病学研究的数据。大量放射生物学数据预测，由于阿尔法粒子产生的高密度电离事件的生物修复机制较差，在低剂量区域会出现线性剂量反应曲线。然而，尚未从“可接受”水平（<4 - 8皮居里/升）证明有令人信服的证据表明癌症风险增加。
