The average daily natural background dose was computed with a statistical approach from the dose records of personal dosemeters worn by professionally exposed workers in Switzerland. The values ranged between 1.3–3.0 $\mathrm{\mu }$Sv/day depending on the geographic location of the customers site. The highest values were found in the Lepontine Alps, the lowest in the Swiss Plateau. The results from measurements with control dosemeters at 31 customer sites were in agreement with the computed values. The geographic variation in the natural background and an inaccurate correction are likely to give rise to differences in dose records by up to 0.1 mSv/month. For quarterly surveillance periods up to 3% of the dose records are expected to be false positives or negatives.

使用瑞士专业暴露人员佩戴的个人剂量计的剂量记录，采用统计方法计算出每日平均自然本底剂量。值范围在1.3–3.0之间$\mathrm{\mu }$Sv /天，具体取决于客户站点的地理位置。最高值出现在Lepontine阿尔卑斯山中，最低值出现在瑞士高原。在31个客户地点使用控制剂量计进行的测量结果与计算值一致。自然背景的地理变化和不正确的校正可能导致剂量记录的差异高达0.1 mSv /月。对于季度监测期，预计最多3％的剂量记录为假阳性或阴性。