Agricultural machines such as sprayers can be improved by providing pressure sensors inside and outside of the operator cab, a cab sensor for sensing an open or closed state of the operator cab, and a controller configured to activate/deactivate an airflow system according to the pressure sensors and the cab sensor. Accordingly, the controller can activate the airflow system to provide a positive pressure differential in the operator cab (higher pressure in the operator cab/lower pressure external to the operator cab), and deactivate the airflow system when the operator cab is in the open state to maximize the life of the system.
