An approach to setting radiation standards

To quantify the concept of a radiation dose which is small compared with the natural background it is suggested that this figure should be interpreted as the standard deviation (weighted with the exposed population) of the natural background. It is considered that this use of the variation in natural background radiation is less arbitrary and requires fewer unfounded assumptions than some current approaches to standard-setting. The standard deviation is an easily calculated statistic that is small compared with the mean value for natural exposures of populations. It is an objectively determined quantity and its significance is generally understood. Its determination does not omit any of the pertinent data. If, as a result of new measurements, additional information on the variance in natural background becomes available, the appropriate adjustment of the standard deviation is readily made and does not require new decisions and debate. (U.K.)