Gas drops by a dollar when you cross the California state line.
Taxes in part. Special refining formulations in part.
Do Californians think the air is dirtier in Oregon?
In a lot of places gas is about $2.60. California is a train wreck.
The problem for California isn’t entirely related to it being a train wreck, although there’s a good case to be made that California is a train wreck.
California formulates it’s gas differently. It does so because it had a serious problem with smog. The air is a lot cleaner today due to the formulation. The formulation changes during the winter and summer months also.
I can remember many days in the 70s where I could see a thick haze in the air even looking at objects half a block away. I don’t see days anywhere near that bad even one day of the year any longer.