Yamato A
Radioisotopes. 1981 Feb;30(2):104-8. doi: 10.3769/radioisotopes.30.2_104.
Measurements of 239, 240Pu and 90Sr were performed on air-dust samples collected by means of filtration with cellulose-asbestos filter at Ibaraki prefecture, Japan during 1974 to 1979. The ranges of 239, 240Pu and 90Sr content determined in these samples are 0.041-1.9 microBq/m3-air (1.1-52 aCi/m3-) and 2.3 87 microBq/m3-air (0.062-2.3 fCi/m3) respectively. The activity ratios of 239, 240Pu/90Sr are found to be in a range between 0.008 to 0.026 with a mean value of 0.017. General trend on time variation of the content of 239, 240Pu and 90Sr in the surface air was in similar pattern each other. The content of these nuclides increased after the Chinese nuclear test explosions, and also in spring seasons with the exception of a few cases.
1974年至1979年期间，在日本茨城县，使用纤维素石棉过滤器通过过滤收集空气尘埃样本，对其中的钚-239、钚-240和锶-90进行了测量。在这些样本中测定的钚-239、钚-240和锶-90含量范围分别为0.041 - 1.9微贝克勒尔/立方米空气（1.1 - 52皮居里/立方米）和2.3 - 87微贝克勒尔/立方米空气（0.062 - 2.3微微居里/立方米）。钚-239、钚-240与锶-90的活度比在0.008至0.026之间，平均值为0.017。地表空气中钚-239、钚-240和锶-90含量随时间变化的总体趋势彼此相似。这些核素的含量在中国进行核试验爆炸后增加，并且除少数情况外，在春季也会增加。
