Average human being is exposed to 0.62 rem of nuclear radiation. Half of this radiation comes from natural background radiation in the atmosphere and other half comes from man-made sources. Some examples of such man- made sources are medical sources such as X-rays and nuclear medical procedures involving I-131, Cs-137 and from consumer products such as building and construction material, combustible fuels, x-ray security systems, TVs, Fluorescent lamp starters, smoke detectors (Americium), luminous watches and clothing (Tritium) and tobacco per U.S. Nuclear Regulatory Commission.
We have used radioactivity for making human life better in terms of keeping the food fresh (irradiation of food), in treating cancer, in making our nation safe (scanners at the airports), in smoke detectors, in stopping crime, as an alternative fuel for space rockets, and most of all, as a possible alternative source of energy in this energy dependent world with depleting fossil fuel s.
Though the benefits of nuclear energy are many, there are safety concerns among public in terms of usage, disposal and their impact on human life. There are studies positively linking ionizing radiation to cancer in high doses but there is no clear linkage between the low doses of ionizing radiation and cancer, according to American Cancer Society.
There are no official guidelines for radiation exposure or prevention in the U.S.A but the Health Protection Agency of the U.K. has issued the guidelines for safe exposure to the radiation and to educate people about the radiation.
In the meantime, it is upon us to make the right choices in terms of radiation exposure that serve our needs and our health the best!