Electromagnetic emissions have been known to be a problem since not long after they were discovered.
Yup, it's called TEMPEST and I was dealing at the time with researchers that managed to read a calculator across the courtyard of the embassy where it was demonstrated (that was to challenge sensitivity, the then CRT monitors were no challenge at all, and only needed a very basic Yagi to pick up). Scary stuff.
So, the news is really that an air gapped computer with seriously sensitive material should only be operated in Tempest-proofed surroundings, which is not really news. At least not after Tempest, and that is quite a few years old as a concept.