Directs the Administrator of the Environmental Protection Agency, in consultation with State and local air pollution control agencies, to undertake a study of air pollution from mobile sources entering the United States from other countries to determine the extent to which air pollution in U.S. areas exceeding national ambient air quality standards is attributable to such sources. Requires development of a verifiable model for estimation of the amount of such pollution and use of estimates and monitoring in at least one metropolitan area near an international border, including the San Diego, California, area, to test model results. Requires a report to the Congress.