We studied the impact of US air quality (AQ) regulations and hypothetical CO2
reduction policy on public health and climate change. We find that AQ regulations are projected to have strong health benefits in the near future but result in a positive radiative forcing (RF), ~ 0.8 W m−2
, over the USA. Under the US CO2
policy we find air quality co-benefits. However, despite CO2
reductions, it leads to overall positive RF (+0.22 W m−2
in 2055) over the USA mainly by lowering SO2
via less coal usage.