[dogben]

My geiger counter activity goes up when air conditioner is working. Never figured out why. This could be a good explanation.

[detrites]

Does your AC include a negative ion generator for cleaning the air? I wonder if that could be affecting it?

[dogben]

I don't think it has negative ion generator. I guess the fan itself can generate ions, that's why aircraft have static dischargers.

[Cerium]

Is your interior AC unit or its ducting in a basement or crawlspace?

[dogben]

It's interior. No ventilation. I guess it's ionizing the air and bringing radioactive dust particles to the whole room. The radiation level is still very low so I'm not worried.