A gas treatment system for treating a gas stream containing contaminants includes first and second gas treatment members in fluid communication with each other. Each of the first and second gas treatment members is selectively controllable between an on and an off condition. A third gas treatment member is in fluid communication with the first and second gas treatment members, and the third gas treatment member selectively retains or releases the contaminants based upon the on or off condition of at least one of the first or second gas treatment members.