An apparatus and method for cleaning contaminated air in an enclosed space, such as a transportation trailer or a shipping container. An air mover in the space circulates contaminated atmosphere from an area of low pressure to an area of higher pressure. The resulting pressure differential is used to draw a reverse, partial air flow through an air cleaning device. The repeated cycling of a portion of airflow results in cleaning of the atmosphere and a general reduction of the contaminant from the enclosed space.
