Background radiation has always existed and is mostly good for us.
- Sunlight is necessary for plants to grow and helps us to feel well.
- Ultra-violet light from the Sun allows us to turn healthy cholesterol under our skin into Vitamin D that in turn fights of: colds/CoViD/’flu and more than 200 other named diseases.
- Infra-red light can relieve pain as well as being how toasters work.
- Short and medium radio-waves allow radios to work.
- Long-radio-waves allow communication across huge distances (e.g. UK to Australia!)
- Microwaves can cook food as well as being the radiation type used by Wi-Fi and mobile phones.
All of those are non-ionizing radiation types that we encounter everyday. Almost all of those occur naturally and so have always existed in the background. All are considered safe at low levels.
Yet… All are harmful at high doses! Yes, non-ionizing may sound nice and friendly but think: Sunburn, Serious-skin-troubles, burns, headaches and brain-tumours from long periods with a mobile pushed against an ear. There are many examples of early use of radiation that at first seemed safe that then did great harm, such as early RADAR operators becoming very unwell.
The less well understood background radiation is the ionizing kind. We cannot see or feel this. It is mostly at such tiny levels it is hard to measure at all.
You may be surprised that there are no known/provable cases of anyone on the surface of the Earth being harmed by background ionizing radiation. Miners may be at risk while in confined spaces surrounded by radioactive rocks but other than from breathing/ingesting toxic dust there is no clear evidence of background radiation harming miners.
Every day, we are all hit by thousands of invisible potentially ionizing cosmic rays. Fortunately our cells repair any damage caused by typical levels of cosmic rays. Even airline pilots who are hit by far more of these than almost anyone else do not have especially high rates of cancer. Going into space presents radiation risks far greater than almost anywhere on Earth, but for the rest of us… background radiation is not harming us.