An air pollution control apparatus according to an embodiment of the present invention includes: a stack that discharges flue gas discharged from a boiler outside; a blower that is provided downstream of the stack and draws in the flue gas; and a CO2 recovering apparatus that recovers CO2 in the flue gas drawn in by the blower. The stack includes a controlling unit that suppresses release of the flue gas outside from the stack and suppresses inflow of atmosphere to the stack, and the controlling unit is a channel forming unit that forms a serpentine channel through which the flue gas and the atmosphere in the stack flow.