Measuring device, fresh air conduit, fresh air device and flow-guidance element

The device (4) has an air guiding channel (14) passing into a measuring cross-sectional surface (7) via an outlet cross-sectional surface (13) of a flow guiding element (11), where geometry of the outlet cross-sectional surface corresponds to geometry of the measuring cross-sectional surface. Geometry of an inlet cross-sectional surface (12) of the guiding element differs from the geometry of the outlet cross-sectional surface, where the inlet cross-sectional surface is formed like a slot and is arranged eccentric to a longitudinal middle axis (18) of a fresh air channel (2). An independent claim is also included for a fresh air channel comprising an air filter arranged upstream to an air mass sensor.