The short answer is no. The ARB’s In-Use Off-Road Diesel Emissions Regulation passed 7/26/07 is intended to apply uniformly across all air districts in California, except where certain exemptions were granted as part of the rule (for example in some remote counties in Northern California).
Clients have asked if South Coast AQMD (the LA-OC basin extending into portions of Riverside and San Bernardino Counties) can impose stricter standards because of their greater air quality problems. Again, generally no, however there are certain extra measures being considered by ARB on 9/27/07 which would seek greater emissions reductions in several areas including Ports, railroads, Metrolink trains, heavy duty trucks and some off-road diesel. As it affects off-road diesel, the principle program being planned is the SOON program which applies only to the largest fleets of 20,000 hp or greater. While called an “opt in” program, in fact, as planned, these largest fleets MUST apply for early Moyer-type funding and take whatever actions are funded (more on this when the full program is published).
To learn more about what specific “extra” measures are planned for SCAQMD and the San Joaquin Valley, go to this website:
http://www.arb.ca.gov/planning/sip/2007sip/2007sip.htm