Abstract: An air filter comprising a filter casing defining an air passage from a first opening to a second opening in the filter casing, at least one filter element arranged in the air passage of the filter casing, such that air passing between the first opening and the second opening must pass through the at least one filter element, characterized in that said filter casing is manufactured with at least one sealed access port integrated in the filter casing, wherein said at least one sealed access port can be unsealed to provide an access to the air passage from outside the filter casing.

Abstract: An air filtration cassette extending in a length direction between a first end and a second end, related to an intended air flow direction from the first end to the second end during use, the air filtration cassette comprising a filter material disposed between an outer boundary surface and an inner boundary surface, the air filtration cassette having an interior open space encompassed by the inner boundary surface and the filter material, and having an opening arranged at one end of the open space and being closed at the other end thereof, an average distance between said inner boundary surface and said outer boundary surface at said second end being larger than an average distance between said inner boundary and said outer boundary at said first end, the average distance between said inner boundary surface and said outer boundary surface being the average of all distances between the inner boundary surface and the outer boundary surface in a direction perpendicular to said length direction at a selected pos