What a strange way to pose a question. So, we know that there are risks with electromagnetic waves in X-rays, so we try to limit our exposure to them. But do

What a strange way to pose a question. So, we know that there are risks with electromagnetic waves in X-rays, so we try to limit our exposure to them. But do you, for instance, run a Wifi access point at home? Do you use a cell phone? And you surely know how radios work: electromagnetic waves. To use your phrasing, "what intuition leads to anyone thinking that electromagnetic radiation is safe in large quantities?" While we know something of electromagnetic radiation effects on health, we know almost nothing regarding long term effects of the type that have become our daily environment, because this level of exposure (wifi APs, cell phones) is a very recent phenomenon. But, we could find out in the long run that they have a non-negligible effect on a part of the population that it may end up being classified as "pollution" in the future too. The point is that people disagree on what are "large quantities" with exhaust gasses (even different governments do, which is why there are different standards), or where do we draw the line. Going with the extreme example can actually be counterproductive because it can easily be proven irrelevant. The other problem with air pollution from cars is that it's conflated with global warming today (not saying it's not an issue, just that everyone wants to solve both problems at once). One can easily solve for one problem without solving for another (eg. allow only use of clean vehicles during peak hours as a pretty light restriction, to banning non-clean vehicles only in dense urban areas as a pretty strong one).