The sources of radiation / 中国辐射卫生

For ordinary people, when it comes to nuclear, radiation occurs to their mind, for fear of nuclear. In fact, radiation is almost everywhere. More than 80 percent of our exposure is from natural sources and only less than 20 percent is human made-mainly from radiation applications used in medicine. The dose we absorb from natural background radiation is about 2.4 mSv per year.