It's not just CARB but quite a few major metro areas outside California were having difficulty improving their air quality during the late 1990's and early 2000. Metro-Atlanta for example and we still have severe air quality days during the summer months though not as bad as what it was back then (no longer on the map as a nonattaintment area).
Dallas, Huston, NJ, CT, N. Illinois, N Indiana, etc all continue to have air quality issues. I remember the air quality in Houston being especially bad. Living near the astrodome I could occasionally smell the chemicals in the air from the refineries/chemical plants 10 miles to the E and SE.
Nonattainment areas in the US