I can’t find any support for your claim that natural gas is “a few percent” of the “pollution” of natural gas.
In GHG terms natural gas is still a fossil fuel that emits CO2. Web searches suggest the number is somewhere between 50% less GHG emissions to a few percent more GHG emissions for natural gas vs coal. This is because natural gas has the additional issue of widespread fugitive emissions across the supply chain which emit methane, an even more potent GHG which itself breaks down to CO2.
As with everything it’s complicated but it’s simply unbelievable that a natural gas plant is anywhere near a 90% improvement over a coal plant which is my arbitrarily generous standard for “a few percent”.
Ultimately there’s just no good way to burn fossil fuels.
I’m not sure what California Air Emission Regulatory is. Do you mean CARB?