A pneumatic conveying system for conveying hydrated lime is provided with ambient air for the pneumatic conveying system from a scrubber that removes carbon dioxide from the ambient air used in the conveying system. The scrubber includes a bed of hydrated lime through which ambient air is passed, to react carbon dioxide in the air with the hydrated lime in a reaction that forms limestone and water. The air that has passed through the fluidized bed, which is essentially carbon dioxide free, is also passed through a filter to remove particles suspended in the carbon dioxide free air. The carbon dioxide free air from the filter is provided to the pneumatic conveying system. The use of carbon dioxide free air ensures that the hydrated lime being transported in the conveying system will not react in the various conduits and ducts of the pneumatic conveying system to cause problems.