Dilution is only a solution if the total amount isn't harmful once diluted. That's not the case for greenhouse gases, at the very least. To say nothing of the other end of the equation: limited supplies of the raw ingreadients. The earth could likely only support a fraction of the current human population if they all lived rural lifestyles.
That long debate aside, today we can see the palpable smog in big cities vs the clean air in rural areas, small towns, and small cities.
You also risk ozone depletion in areas with concentrated aerosol emissions, these are short lived and would disperse, but they cause the most damage of all pollutants in concentration.
> The earth could likely only support a fraction of the current human population if they all lived rural lifestyles.
I'm not suggesting that, I'm suggesting people live where they want to and don't fall for that inaccurate guilt-trip talking point.
Concentrating in one spot will be more efficient but cause more damage than dispersing.
The efficiency you gain in centralizing is irrelevant since you lowered the total but concentrated it so it can grow instead of disperse.
Which is worse, dumping a ton of salt in one spot in the ocean or dumping 1.2 tons throughout a large area?
There's a reason cities generally have smog and towns generally don't.
Dilution is the solution to pollution.