摘要：

The background radiation measurements in the lower atmosphere at different altitudes above sea level up to 1100 m and over the land were made at a temperate latitude ( 40°) in the Thessaloniki region, North Greece, before and after the Chernobyl accident (26 April 1986), using a portable γ-ray scintillation detector and a Cutie-pie survey meter with an ionization chamber. The average value of the total background radiation at ground level was 87 nGy h~(-1) (10.0 μR h~(-1), 25 cps), i.e. 60/100 from terrestrial radiation, 55 nGy h~(-1) (6.3 μRh~(-1), 15 cps) and 40/100 from cosmic radiation, 32 nGy h~(-1) (3.7 μRh~(-1), 10cps), before the Chernobyl accident, while, after it, the total background radiation was doubled, due to the long-lived radioactive fallout suspended in the atmosphere and or deposited onto the ground.

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