wiping the car down

I saw an experiment suggested somewhere that after rain, one should wipe the car down and expose the counter to the wet towels - I've just done that, and am quite amazed to see up to 90cpm instead of the usual background count that I get in NE Essex of around 20 - 24. Within a few moments, the level has fallen back to around 55cpm, but it does make the thought of getting wet in the rain a tiny bit more alarming !!

Nick

When I got home yesterday after a rain I took a reading of my rain barrel. It started at 34 CPM but over 5 minutes averaged 22 CPM which is slightly above my normal indoor reading of 20. I don't give much credence to short-term readings, but I will continue doing this with shorter delay after the rain, and maybe use an overflow bucket to avoid dilution. There are many reports of this effect on youtube, with some consensus that it is natural and mostly washed down Radon with half life of 3.8 days (see livescience.com )