A work vehicle having an operator cab comprising an operator's chair and an HVAC system, the system being positioned substantially within the cab behind and below the operator's chair, a portion of the system having at least one inlet, and a plurality of outlets positioned in front of the operator's chair, the system including a chamber positioned in the interior of the cab and behind an operator's chair, the chamber having a first inlet for receiving an exterior airflow from outside of the cab, the chamber having a second inlet for receiving an interior re-circulated airflow from air contained within the cab, the chamber mixing the exterior airflow with the interior re-circulated airflow to form a mixed airflow which is directed substantially vertically downward out of a chamber outlet, characterised in that the system further includes: a filter positioned in a conduit connected to the chamber outlet and in fluid communication with the chamber, the first inlet, the second inlet, and the plurality of outlets, the filter positioned below the chamber in a substantially horizontal position relative to the substantially mixed airflow flowing through the chamber to an upper surface of the filter, the substantially vertical mixed airflow moving through the filter and through the plurality of outlets in the HVAC system such that airflow from the plurality of outlets circulates over and around the operator's chair, providing a generally circular path of airflow about the operator's chair, at least a portion of the circular airflow re-entering the chamber as interior re-circulated airflow, wherein the filter is configured to trap debris from the vertical mixed airflow via its orientation and the filter is configured for easy removal by an operator inside of the cab, and wherein the filter is configured to be easily maintained in its substantially horizontal position during removal so that debris retained on the upper surface of the filter does not fall into a portion of the HVAC system or the cab when the filter is removed therefrom. a filter positioned in a conduit connected to the chamber outlet and in fluid communication with the chamber, the first inlet, the second inlet, and the plurality of outlets, the filter positioned below the chamber in a substantially horizontal position relative to the substantially mixed airflow flowing through the chamber to an upper surface of the filter, the substantially vertical mixed airflow moving through the filter and through the plurality of outlets in the HVAC system such that airflow from the plurality of outlets circulates over and around the operator's chair, providing a generally circular path of airflow about the operator's chair, at least a portion of the circular airflow re-entering the chamber as interior re-circulated airflow, wherein the filter is configured to trap debris from the vertical mixed airflow via its orientation and the filter is configured for easy removal by an operator inside of the cab, and wherein the filter is configured to be easily maintained in its substantially horizontal position during removal so that debris retained on the upper surface of the filter does not fall into a portion of the HVAC system or the cab when the filter is removed therefrom.