Abstract: A computer implemented method of operating an air cleaning cluster (20, 20?) comprising a plurality of air cleaning devices (10, 10.1-10.n) interconnected to each other by a volume of air (100), each air cleaning device (10, 10.1-10.n) being configured to remove contaminants from the volume of air (100), the method comprising: receiving, by control device(s) (30, 30?, 30? 30.1-30.n) from air quality data sources, data indicative of air quality within the volume of air (100); receiving, by the control device(s) (30, 30?, 30? 30.1-30.n), data indicative of operational state(s) of the air cleaning devices (10, 10.1-10.n); and the control device(s) (30, 30?, 30? 30.1-30.n) controlling the air cleaning device(s) (10, 10.1-10.n) of the air cleaning cluster (20, 20?) such as to influence the indoor air quality within the volume of air (100), using the data indicative of the indoor air quality and the data indicative of an operational state of the plurality of air cleaning devices (10, 10.1-10.n).

Abstract: An air filter arrangement (A) includes at least two frames removably attached to each other, each one of the at least two frames delimiting one of at least two spaces/volumes (V1, V2, V3) and all of the at least two frames together defining an air flow path (V1-V2-V3) passing through each one of the at least two adjacent/contiguous spaces/volumes (V1, V2, V3), wherein the space/volume (V1, V2, V3) of one frame of the at least two frames includes a first air filter (F1), the space/volume (V1, V2, V3) of another frame of the at least two frames includes a second air filter (F2), and the space/volume (V1, V2, V3) of one frame of the at least two frames includes an air moving unit (M1). A combined air filter arrangement (CA) may include at least two such air filter arrangements.