In this study, we estimate potential synergy between pollution and climate control in the U.S. and China and conduct a cross-country comparison. When measured as cross-emissions elasticity, ancillary CO2 abatement from unit % reduction of NOx and SO2 emissions is substantially greater in China under stringent targets, though comparable between the two countries under moderate targets. In contrast, NOx and SO2 abatement from unit % reduction of CO2 emissions is much greater in the U.S. than in China, regardless of the stringency of the policy shock. These results are primarily driven by China’s higher dependence on coal, as coal has larger unit emission-reduction effects than other fossil fuels and its intensive use creates more room for less costly fuel-switching and abatement options. In addition, pollution-abatement co-benefits of carbon mitigation tend to be greater than carbon-mitigation co-benefits of NOx and SO2 reduction in the U.S., while the opposite is the case for China. The relatively low pollution-abatement effects of carbon mitigation policy in China are primarily due to the expanded role of carbon capture and storage technology, which keeps coal from being crowded out of the energy market by reducing its carbon emission factors, but without affecting NOx and SO2 emissions. Our study suggests that some countries like China may consider it more appealing to pursue the synergy from a pollution-control perspective than from a carbon-mitigation standpoint, given the former’s greater synergistic effects. In this sense, future co-benefit studies need to pay more attention to carbon co-benefits of pollution abatement—the opposite logic of the currently dominant focus.