I don't think it's hard to make this claim hold up at all. Have you looked at local differences apart from comparing HUGE countries with each other; one of whic

I don't think it's hard to make this claim hold up at all. Have you looked at local differences apart from comparing HUGE countries with each other; one of which has an extremely low population density? Since you are mentioning walkable "very similar" infrastructure, how do you quantidy actual walkability? It takes a single search to find many different studies and meta-studies about correlations between noise, air pollution and mental illness, cardiovascular health, life expectancy and others. I encourage you to look for studies about a metropolitan area near you: Car traffic is not harmless. Noise is not harmless. It's just that those who contribute the most to pollution anr noise usually don't experience it every day for hours on end, or even during their sleep. If you prefer esoteric subjects to obvious ones, I'd recommend this study: https://www.mdpi.com/2073-4433/11/5/467 https://www.mdpi.com/2073-4433/11/5/467 If you are looking for proofs for the obvious (living at a busy road makes you sick), there are plenty of studies about this subject as well. Cancer rates rise, IQ drops, life expectancy drops, all in clear correlation to your immediate environment. As a German, also the pedestrian's and cyclist's utopia that Europe is painted as on US media also sickens me. It's purely a matter of money and inheritance. Good luck finding a non-toxic place to live in a big city with an average wage and *without owning a car*. Possible, but exceptional.