[defrost]

It's worth bearing in mind that:

    Before 1963, the United States and other countries conducted more than 500 nuclear weapons tests in the atmosphere. During these tests, radioactive particles and gases were spread in the atmosphere.

    Radioactive fallout was deposited all over the world, so many people were exposed to it. Even today, radioactive fallout is present in all parts of the world in small amounts.

https://www.cdc.gov/nceh/radiation/fallout/rf-gwt_home.htm

Don't forget to compare the fallout from your nearest nuclear power plant to the radiation from radon gas expressed daily by your nearest granite outcrops. If you live in a valley with nearby granite it's quite likely your vally "fills" with radon gas every day when the winds are still and bows clear when the wind picks up.

https://www.epa.gov/radiation/what-radon-gas-it-dangerous