It really doesn't matter when the reading was taken to be honest,they are both so low that they wouldn't warrant any concern.
The effects of this radiation on humans cannot be measured by a reading such as this, as it would be incorrect to do so.
- This is an air reading i.e. it is a measure of energy absorbed per unit mass of air.
- It doesn't have a quality factor for the radiation.
- It doesn't account for the absorption rate of human tissue.
So how to we convert Air Kerma across an unknown range of Ke(γ) to human equivalent dose???
I hope the above illustrates how ludicrous it is to try to apply units of Grays measured in free space to equivalent dose absorption in humans.