To investigate the publics' internal exposure by inhalation of radiocesium from the Fukushima Daiichi nuclear disaster in 2011, we examined the activity of radiocesium and radiocesium-bearing particles adhering to nonwoven fabric masks worn daily by members of the public in spring 2013 and 2014. We found a maximum cumulative Cs activity of 4.58 ± 0.15 Bq in 4 wk of spring 2013, which is 20.8% of the activity measured for the same subject in spring 2012 using the same method. This decrease was faster than the physical decay of radiocesium. Radiocesium was detected in 21 of 722 masks in 2013; three of these included type A radiocesium-bearing particles. The activity ratio of the radiocesium-bearing particles on the mask to the total radiocesium was at most approximately 20%. The two radiocesium sources, radiocesium-bearing particles and fugitive dust, are both insoluble particles. The largest internal dose from inhalation was 7.6 μSv in spring 2013, which is negligible compared to the dose limit recommended for members of the public by the International Commission on Radiological Protection.

中文翻译：

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2013年春季，在福岛市民佩戴的口罩中发现了含放射性铯的颗粒。

为了调查2011年福岛第一核电站灾难中吸入of引起的公众内部暴露，我们研究了2013年春季和2014年公众日常佩戴的无纺布口罩上附着的放射性铯和带有放射性铯的颗粒的活动。发现在2013年春季的4周内，最大的Cs累积Cs活性为4.58±0.15 Bq，这是使用相同方法在2012年春季对同一受试者测得的活动的20.8％。该下降速度快于放射性铯的物理衰减。2013年，在722个口罩中，有21个检测到放射性铯；其中三个包括A型放射性铯颗粒。掩模上的含放射性铯的颗粒相对于全部放射性铯的活性比至多为约20％。两种放射性铯源 含放射性铯的颗粒和逃逸的粉尘都是不溶性颗粒。2013年春季，吸入的最大内部剂量为7.6μSv，与国际放射防护委员会为公众建议的剂量限制相比可以忽略不计。