An HVAC system for a work vehicle having an operator cab includes a first chamber having an for receiving airflow exterior of the cab. The inlet is adjacent to a first source for moving air for use independent of the HVAC system, the inlet arranged to cause a first change of direction of airflow inside the first chamber. The first chamber resulting in both a first air pressure reduction and a first reduction of airflow velocity while inside the first chamber sufficient to reduce an amount of particles entrained in the airflow while the particles are within the first chamber. A second chamber in fluid communication with the first chamber and configured to cause both a second change of direction and a third change of direction of airflow while inside of the second chamber prior to reaching a third chamber for mixing air flow with recirculated air from the cab.