Sure, but coal power plants are kind of whataboutism here and doesn't mean that nitrous impact doesn't exist. In the hospital setting, it seems that reclaiming nitrous, instead of releasing it into the environment, might be a feasible option as well; It would just costs more money.

Yes, despite nitrous being widely used for labor in the US, 30 or 40 years ago, then falling into disuse for epidurals and largely forgotten. For some reason it seems still widely used in Australia. I do think the risks of epidurals is under-rated, and long term problems glossed over, but on paper they are super safe. Nitrous seems well documented to be problematic, where many in labor can't handle it. Personally, for dental procedures, I can't handle it myself. From my exposure at the dentist, nitrous is fun and all, and seems great for parties, but when the dentist gets to doing his thing it makes me freak out.