RFI in general:
Having chased RFI from the 80's, to this day, and a family member in the
industry to locate, identify, and mitigate it, working from hobbyist, to
commercial, to DARPA, I can say...
It doesn't even matter.
RFI/EMI is not a definitive thing, it can exist wherever there is
energy, and exists in a unique manner comparable to all the grains of
sand on earth, and there is no "specifically" about any of it.
There is no one frequency, or type, other than that produced by each
individual source, although there may be some commonality, for example
power lines, which produce RFI, generally beginning at 60 Hz, and that
I've heard directly to 2.3 GHz, the 38,000th+ harmonic, with one single
source traced to a single connection, affecting 18 square miles.
If you experience it, address that RFI, from the source affecting you at
that moment (then expect to find up to several dozen more at your
location, it's that rampant). That will not, unfortunately, prevent one
from being affected by the several billion devices generating it
globally 24/7/365, any given instant, which, hopefully, won't affect
you, because, good luck getting the rest of the world to turn off.
That being said, however, not all RFI/EMI will affect a particular
installation, which makes things easier. If you aren't experiencing RFI
from arcing power lines, don't bother that find, and fix it. Same with
WiFi, any one of dozens of monitors, or displays, LED lights, switching
mode power supplies, et cetera.
Address RFI/EMI, per source, per device affected.
Kurt