The American Trucking Association has appealed a U.S. district judge’s ruling that allows the Ports of Los Angeles and Long Beach to implement its program to lower air pollution by banning older, more polluting trucks from the ports.

Judge Christina Snyder earlier this week declined to impose an injunction stopping implementation of the ports’ program.

The ports’ Clean Trucks Program requires trucking firms to obtain a concession from the ports, retire older model trucks and dispatch only drivers who have undergone a security background check and obtained a federal transportation worker identification credential.

Port officials have said that the concessions provision is a key element in implementing the clean trucks program.

The association, in an appeal filed late Wednesday, said it supports the phased retirement of older trucks from port operations, but considers the concessions requirement an attempt by the ports to impose restrictions on motor carriers in violation of federal law.