Honestly, I would guess the smart meter in the woods would radiate more power than in the city since there are few other smart meters near; so I would conclude that most people would experience less RF. And in the city, there are more smart meters (likely though at lower power) but also more wifi, so the relative density of EMF between smart meters and wifi would be similar I guess. So for a rough order of magnitude, yes, I think the results are valid.
I don't know much about infrared, but I know quite a bit about RF and standing 2 meters from the smart meter, I don't think oxygen absorption would have much effect on the results.
My point, to be explicit, is that it appears that smart meters produce a de minimus effect on EMF when considered in conjunction with wifi, cell phones, and AM/FM radio, principally because of the ephemeral nature of the signal.