Policy spillovers, technological lock-in, and efficiency gains from regional pollution taxes in the U.S.

•Simulated regional and national emission-tax policies in the United States using the US-TIMES energy-system model.•Observe electric sector technology lock-in depending on the timing of CO2 and air pollution tax policies.•Simulated emissions damages across tax policies using integrated assessment models for air pollution: AP3, EASIUR, InMAP.•Simulated net benefits are higher under a regional versus a national air pollution tax regime.•Substantial policy spillovers present under CO2 and local air pollution tax policies.