and any combinations thereof that are entrained within or carried by the air drawn through the scrubber 131 a mist eliminator 133 is disposed at the upper end of the scrubber 131 to prevent such droplets or spray from being drawn upwardly out of the scrubber 131 through the scrubber outlet duct 134 the scrubber may be made in accordance with any of u s pat nos 3 969 094 4 539 024 and 5 292 353 or in any other manner water is delivered to the one or more spray nozzles 132 in the scrubber 131 via a delivery line 135 preferably under pressure provided as by a pump 136 controlled by a motor 137 that in turn is controlled via an electrical control line 138 from the programmable logic computer c droplets that dissolve or absorb the dust odor particles steam ammonia or other impurities are collected at the bottom of the scrubber 131 and may be discharged therefrom via the liquid discharge line 140 it will thus be seen that pollutants are removed from the air entering the scrubber 131 the thus purified air passes through the scrubber discharge duct 134 to enter the bottom of a stack 141 that is supported on a stack support tower 142 a fan impeller or other air movement device 143 is located in the stack 141 as shown in the cross section.