Radioactivity is how dangerous?
the Natural (background) ionizing radiation is not dangerous to the population. The person lived in such world always. Excess of level of a background is dangerous.
The annual dose from all natural sources of the ionizing radiation averages 1 millisievert (mzv) in a year on the person. The safe annual dose for professionals in 50 times more also makes 50 mzv. The easy stage of radiation sickness comes at a dose of 1 Stars. Radiation of the sun is not a component of the natural ionizing background. It is not necessary to confuse space ionizing radiation and solar radiation in the visible, infrared and ultra-violet range of an electromagnetic range.
Of what there is a background radiation? In - the first, a space component. Its rigid part (protons and more heavy-nuclei with high energy) at interaction with the atmosphere of Earth forms the secondary ionizing streams (mezona, neutrons, protons, electrons, scale - quanta) which influence the person. Average annual dose 0,3 mzv.
In - the second, scale - the radiation of rocks and food. The matter is that the earth on which we go stone and concrete walls of houses, food and other objects around us contain natural radionuclides in a scattered state: carbon - 14, potassium - 40, rubidium - 87, thorium - 232, uranium - 235, - 238, etc. An annual dose - about 0,5 mzv. It is less natural radionuclides in a tree, than in stone building materials. Therefore in wooden houses (in this parameter) life is healthier.
In - the third, ourselves are radioactive. In the adult`s body on average there are 3000 disintegrations a second at the expense of potassium - 40, consumed with food. An annual dose from this component - 0,2 mzv. In - the fourth, there are artificial sources of radiation. Power of an exposition dose from the color TV with ELT makes 0,43 ?Sv/hour at distance of 5 cm from the screen. Flight by plane at the height of 9 km - 7 ?Sv/hour. Let`s note that the additional annual dose of radiation of the population living near the NPP (10 - 50 ?Sv) is comparable with an additional dose of radiation of the person during one flight by jet plane (1 - 8 hours). But we do not refuse planes.
Once again I will emphasize that background radiation is natural and safe for the person . On that it and background.
I will give some other chemical dangers which we usually ignore for comparison. There is an opinion that “national peculiarity“ of Russians is ability “much to drink“. And so on genetic action (on chromosomal aberrations) 18 bottles of vodka are equal to a dose in 0,2 Stars / year (4 professional), 6 cups of coffee daily - a dose 8,4 mzv / year. I provide to readers to consider what harm you do yourself one way or another (and can be, in common).
It is simple to control a radiation background. It is much simpler, than to organize monitoring (continuous control) of chemical pollution of the city. Power of an exposition dose, for example, in Khabarovsk is measured daily in the Center of Gossanepidnadzor by office of radiation hygiene. Out of the room at distance of 1 m from the Earth`s surface the background fluctuates within 11 - 12 ?R/hour. I will specify that over a surface of the water it is usually equal to 4 - 5 ?R/hour, in kamenno - concrete houses 15 - 25 ?R/hour
the Example from our recent reality.
About the only situation connected with radiation hazard for health of residents of Khabarovsk, now, apparently, it is possible to tell. As it is known on April 26, 1986 there was a Chernobyl accident. At this time I worked as the engineer - radiometristy KRAYSES. On May 5, 1986 the message arrived that the baggage of group of the Japanese tourists departing to Niigata “shines“. Having arrived to the international terminal of the airport, our group made a radiation control of tourists and baggage. It turned out that tourists were on May 1 - 3 in Kiev and all clothes which were in public at this time, and also the surface of suitcases was radioactive (excess of a background by 10 - 20 times).
Deactivation of a surface of baggage was carried out, and the radioactive clothes are withdrawn and placed in a warehouse of radioactive material transportation packages of the airport where it was maintained till November, 1986. By this time short-lived radionuclides broke up. The clothes became safe. I will in passing disprove the ordinary myth. Japanese had no individual dosimeters.