消核辐射恐慌 世卫组织权威解答核辐射疑问

世界卫生组织3月15日在其官方网站上发布日本核爆炸事件相关问题集，为民众解答核辐射后如何保护自己的相关问题。其中特别提及：什么是电离辐射？辐射会产生哪些急性健康问题？是否应该服用碘化钾片？等。来看看有没有提及你的疑问。

FAQs: Japan nuclear concerns
日本核爆炸事件相关问题集

1. What is the current risk of radiation-related health problems in Japan to those near the reactor at the time, and those in other parts of Japan?
目前就反应堆附近和日本其他地区来讲，核辐射健康问题的威胁有哪些？

The actions proposed by the Government of Japan are in line with the existing recommendations based on public health expertise. The government is asking people living within 20km of the Fukushima Daiichi nuclear power plant to evacuate and those between 20 km and 30 km away from the plant are asked to stay indoors in unventilated rooms. People living farther away are at lower risk than those who live nearby.
日本政府提出的行动和目前和以公共健康专业知识为基础的建议是一致的。政府呼吁居住在福岛核电站20公里以内的居民赶紧撤离，居住在距核电站20-30公里之内的居民呆在家里，关闭门窗。居住在远处的居民受到的威胁要比附近的居民受到的威胁要低。

This assessment can change if there are further incidents at these plants and WHO is following the situation closely. However, radiation-related health consequences will depend on exposure. Exposure in turn is dependent on the amount of radiation released from the reactor, weather conditions such as wind and rain at the time of the explosion, the distance someone is from the plant, and the amount of time someone is in irradiated areas.
如果这些工厂发生进一步的事故，该评估可能改变；世卫组织正在密切关注目前的局势。然而，核辐射的健康后果取决于暴露的程度。反之，暴露程度取决于从反应堆释放出来的辐射量，爆炸发生时的天气情况，如风力和降雨，以及当时人们的位置与核电站的距离，人们在核辐射区域呆的时间。

2. What is ionizing radiation?
什么是电离辐射？

When certain atoms disintegrate, either naturally or in man made situations, they release a type of energy called Ionizing radiation (IR). This energy can travel as either electromagnetic waves (gamma or X-rays) or as particles (neutrons, beta or alpha).
当某些源原子分解的时候，无论是在自然条件下还是在人工条件下，它们都会释放出一种被称为电离辐射的能量。这个能量能够像电磁波（伽马射线或X射线）或者粒子（中子，β或α）那样传播。

The atoms that emit radiation are called radionuclides.
释放出辐射的原子被称为放射性核素。

The time required for the energy released by a radionuclide to decrease by half (i.e., the "half-life") range from tiny fractions of a second to millions of years depending on the type of atoms.
放射性核素释放的能量减半需要的时间范围是几分之一秒到几百万年，取决于原子的类型。

3. Are people normally exposed to ionizing radiation?
人们通常都暴露在电离辐射下吗？

Human beings are exposed to natural radiation on a daily basis. The radiation comes from space (cosmic rays) as well as natural radioactive materials found in the soil, water and air. Radon gas is a naturally formed gas that is the main natural source of radiation.
人类每天都暴露在电离辐射下。辐射来自于外层空间（宇宙射线），以及在土壤，水和空气中的天然放射性物质。氡气是一种自然形成的气体，是主要的天然辐射来源。

People can also be exposed to radiation from human-made sources. Today, the most common man made source of ionizing radiation are certain medical devices such as X-ray machines.
人类同样可能暴露在人为来源的辐射下。当今，最主要的人为来源电离辐射就是某些医疗设备，如X光仪器。

The radiation dose can be expressed in units of Sievert (Sv). On average, a person is exposed to approximately 3.0 mSv/year of which, 80% (2.4 mSv) is due to naturally-occurring sources (i.e., background radiation), 19.6 % (almost 0.6 mSv) is due to the medical use of radiation and the remaining 0.4% (around 0.01 mSv) is due to other sources of human-made radiation.
辐射剂量可以西弗特（Sv）为单位。平均来说，一个人每年接触到的辐射量约为3.0毫西弗，其中，80％（2.4毫西弗）是由于自然发生源（即，背景辐射），19.6％（几乎0.6毫西弗）是医疗使用的辐射和其余0.4％（约0.01毫西弗）来源于其他人类活动。

In some parts of the world, levels of exposure to natural radiation differ due to differences in the local geology. People in some areas can be exposed to more than 200 times
the global average.
在世界上的有些地区，暴露在自然辐射下的程度会因为当地的地理原因而不同。某些地区的人们可能暴露在高于全球辐射两百倍的辐射下。

4. How are people exposed to ionizing radiation?
人们是如何暴露在电离辐射下的？

Ionizing radiation may result from sources outside or inside of the body (i.e. external irradiation or internal contamination).
身体的内部和外部都有可能成为电离辐射的来源（外部照射或内部污染）。

Internal contamination may result from breathing in or swallowing radioactive material or through contamination of wounds.
内部污染，来源于吸入的或者是吞服的放射性物质，或者通过伤口污染。

External irradiation is produced when a person is exposed to external sources such as X-rays or when radioactive material (e.g. dust, liquid, aerosols) becomes attached to skin or clothes, resulting in external contamination.
当一个人暴露在外来辐射源如X光下，或者当皮肤接触到放射性物质（如灰尘，液体，气雾剂）时，外部照射就产生了，其结果是外部污染。

External contamination can often be washed off the body.
身体外部的污染可以被洗掉。