Actually, it's bizarre, but some people really are affected by some sources of electromagnetic radiation that very few other people are affected by. This is a real phenomenon. Maybe not as common as some of the people who think they're affected by it really are, but some people genuinely do feel effects. Don't know why.
However, LCD panels don't (or shouldn't) emit any sort of electromagnetic radiation that anyone can feel, as long as the LCD is working properly. If Dunlorprl's problem really is due to EMF, it's more likely to be caused by a defective Airport antenna, or something else. Maybe there's a shielding or grounding issue.
But I tend to think there's probably something different about Dunlorprl's iMac's LCD's visual characteristics that are affecting him. Maybe there's something wrong with the LCD's refresh rate.