Maybe the WHO? If the air makes people sick is a pretty objectively quantifiable question. The differences go beyond unit conversion and a main issue is how m

Maybe the WHO? If the air makes people sick is a pretty objectively quantifiable question. The differences go beyond unit conversion and a main issue is how much we are used to tolerate people dying early or having seriously reduced quality of their lives because of pollution. Especially in urban and industrial areas. What adds to the complexity is that air quality can vary significantly within a city. Compare having a flat between two busy roads and a nice house in the suburbs. And compare that flat between two busy roads to a room next to a factory in the global south, or the US, or in Europe. It's a question of how many suicides, cancers, strokes etc we want to tolerate. There are studies quantifying the effects of these "local differences". And they are easy to find. To me, pretending this was a question of culture or genetics is malicious obfuscation of the actual issues - not accusing you personally, but this is the essence of the combination of many of the comments here. Air quality is measurable using several objective categories of pollutants. Standardizing the units is one issue, facing the reality of millions of casualties per year is another one.