Older United States automobiles have been identified as contributing disproportionately to global air pollution  The requirement in many jurisdictions that automobiles pass emission-control inspections has had the effect of taking many such automobiles out of service in the United States, as they fail inspection and their owners opt to buy newer automobiles
Thus the burden of pollution such older United States automobiles contribute to the global atmosphere will be gradually reduced over the next decade
There is a thriving market for used older United States automobiles that are exported to regions that have no emission-control regulations.