An air treatment system is disclosed that includes a modular configuration whereby a fan module, filter module, and humidifier module may couple together to provide a plurality of air treatment solutions. In more detail, the modules can stack end-to-end in a vertical configuration. The modules may electrically couple to each other via a common electrical bus and enable a controller disposed in the fan module (or other module) to control fan flow rates, direction, and humidity. The fan module can include an articulating nozzle capable of directing airflow in virtually any direction and angle about an environment. The fan module can further include an inlet arrangement that can selectively restrict external air from entering the fan module housing when the fan module is fluidly coupled to the filter module. Thus, the fan module may generate air flow from exclusively filtered air to minimize or otherwise reduce bacterial/mold growth within the fan module housing.