Very surprising to me as well! Also, the amount of decrease:
“World anthropogenic background radiation levels peaked at 0.11 mSv/yr above natural levels in 1963, the year that the Partial Nuclear Test Ban Treaty was enacted. Since then, by about 2008, anthropogenic background radiation has decreased to 0.005 mSv/yr above natural levels.”
Very surprising to me as well! Also, the amount of decrease:
“World anthropogenic background radiation levels peaked at 0.11 mSv/yr above natural levels in 1963, the year that the Partial Nuclear Test Ban Treaty was enacted. Since then, by about 2008, anthropogenic background radiation has decreased to 0.005 mSv/yr above natural levels.”