An air pollution control system includes a desulfurization apparatus 13 that reduces sulfur oxide contained in flue gas 12 supplied from a boiler 11; and a CO2 recovery apparatus 15 including a CO2 absorber 21 that reduces CO2 contained in flue gas 12 that has been desulfurized by the desulfurization apparatus, with the aid of an amine absorbent and an absorbent regenerator 22 that regenerates the amine absorbent. Part 14a of desulfurized flue gas 14 containing SOx is supplied to treated flue gas 16, from which CO2 has been reduced and which is discharged from a top portion of the CO2 absorber 21, so that remaining mist amine accompanying the treated flue gas 16 is neutralized to amine sulfate or amine sulfite.