Some air ionizers generate high voltage for ionizing in such a way that they can emit radio waves. They can interfere with AM radios much more easily than FM (frequency range and modulation differences). Air ionizers also emit charged particles, which could, in theory, interfere with or damage a PC. I seriously doubt it would happen, however, because the PC is designed to be hit pretty hard with static electricity "jolts" and survive it. If you live in a dry area, just think about how many times you have zapped your PC when you touch it, and it still works.

I have an air cleaner that uses pulsed high voltage air motion techniques. It does not interfere with radio and has never caused me computer problems. I’m not sure it really does much to clean the air, either, but it doesn’t interfere with anything. I won’t give the name here, since I just dissed the silly thing, but I bet you can guess the brand.

Cheers!