Having lived in Kalifornia, I can say that it's stupid to have one
emission standard for the rest of the states and another for
California.

Like regulation of air traffic, and telecommunications, regulation
of the air which circulates around everyone is a Federal prerogative.

Californians have for years had to pay extra for a CA emission
certified cars. I don't know if it's still so, but it used to
be if you moved to California and brought your car from another
state, and it wasn't one that had the special CA certification (often
just a paper difference), you had to pay a several hundred dollar
'penalty' when first registering it.

There will always be Federal standards; to add yet another layer
is absurd.

What's worse is that California has such a large population that
letting them make a separate 'peace' as regards emissions removes
a big bloc of voter pressure to do things correctly at the Federal
level--- which is where such things really need to happen.

It's bad enough that things like drivers licenses run state-by-state
thus leading to a fragmented system. To regulate air quality standards
in a checkerboard fashion is just nuts.