I'm running some code through the profiler right now. I'm working on improving that function that is using 17% of CPU, rather than the dozens clocking in at less than 1%.

If I can get that 17% function to run in 94% of the time, that is a greater gain from less effort than making any of those <1% functions run in 50% of the time.

The same principle applies to air pollution. Focus on the container ships burning bunker oil and the power plants burning coal first. Personal transportation using internal combustion engines is one of those 1% things, and even then, just taxing the gasoline won't help all that much.

As parent mentioned, it will also stifle the economic activity that could allow ordinary people to afford capital investments like at-home solar energy systems. And while one presumes that a "carbon tax" on gasoline fuel should be used to combat air pollution elsewhere, that is not necessarily how it will be spent.