An air filter has a filter housing with inlet opening, outlet opening, and service opening. A first filter element and a second filter element are arranged inside the filter housing between inlet opening and outlet opening. The first filter element is arranged in a mounting frame. The first and second filter elements can be flowed through serially in one or more operating states of the air filter. The mounting frame is insertable through the service opening into the filter housing in a joining direction and removable from the filter housing opposite to the joining direction. The second filter element has a wedge stop. A clamping wedge arranged at the mounting frame, upon insertion of the mounting frame into the filter housing, contacts the wedge stop of the second filter element and clamps the second filter element at the filter housing in a clamping direction transversely to the joining direction.

An air cleaner assembly comprises a housing and a filter element. The housing comprises a first housing end and a second housing end. The second housing end of the housing defines an opening of the housing for fluid flow. The filter element is configured to be received through the first housing end of the housing. The filter element comprises a filter media and a closed endplate. The filter media comprises a first media end and a second media end. The second media end of the filter media defines an opening of the filter element for fluid flow. The closed endplate is positioned along the first media end of the filter media and comprises a wall with an axially inner surface and an axially outer surface. The axially outer surface is exposed to an area outside of the housing and closes off the first housing end of the housing when the filter element is positioned within the housing.

A system includes a non-transitory computer-readable medium having instructions stored thereon. The instructions, when executed by one or more processors, cause the one or more processors to acquire air quality data regarding an air quality of air upcoming, proximate, or entering an air inlet of a filtration assembly, close or restrict the air inlet in response to the air quality data indicating that the air upcoming, proximate, or entering the air inlet is of a quality lower than a quality threshold to substantially prevent dirty ambient air from entering the filtration assembly, and activate air storage to provide an air supply to the filtration assembly when the air inlet is closed or restricted.

A filter housing includes a housing body having an openable installation opening and a housing cover to close the installation opening, and a fastening and/or locking device to secure the housing cover in a closed position. The housing body includes an element receptacle to receive a filter element through the installation opening. The fastening and/or locking device has a U-shaped bracket element with arm sections connected to a cross beam and an eccentric element mounted rotatable on the cross beam. The bracket element pivots with respect to a bracket pivot axis such that the cross beam with the eccentric element is pivotable on a side of the housing body with the installation opening. In the closed position the eccentric element engages with the housing cover and the bracket element grips the housing cover such that a part of the housing cover is between the arm sections of the bracket element.