Citation for knowing it isn't true for ionizing radiation? LNT is supported by the US NRC, the EPA, and UNSCEAR. Not saying that it supports the papers on EM radiation, but it's definitely not crazy to assume LNT in your research (and given we don't know much about the effects of low radiation doses, it's definitely the more precautionary option).
To give you an intuition though, LNT would suggest that the body has no repair mechanism for healing damage from radiation (should be suspicious about this) and that all effects are accumulative (which makes sense if there is no repair, but doesn't if there is repair). We can heal from other things and have demonstrated in the lab that cells can repair from low radiation dosages.
Basically the thing is that measuring is incredibly difficult because there's a temporal component and effects are very different depending on where that dosage is received (eg. your eyes vs your hands. See equivalent dosage). So what do you do? You overestimate on the side of safety. Failure of modeling is built into the safety standards (I used to work on radiation shielding devices and I fully support the use of the LNT model in practice. Better safe than sorry).
I haven't read all of these and didn't archive what I have read so these are what I came up with quickly (I did read abstracts, of course)
(Short end is that it isn't clear how much cancer risk increases for dosages <100mSv -i.e. "low dosages" -, which is WELL above occupational standards - 5x actually)
Isn't the answer "Denver"? The city has a higher radiation dosage than average yet no more medical issues. Or at least that's something I heard once. A quick google brought up this site (which I have no idea who is sponcering)
