Abstract: A filter device for ambient air filtration has a blower housing with air inlet and air outlet. A device for generating an air flow is arranged in the blower housing and generates an air flow in operation from air inlet to air outlet. A flexible air conducting hose is provided with a first open end connected to the air outlet of the blower housing and with a second closed end. The flexible air conducting hose has openings arranged between first open end and second closed end. Filter elements are arranged in the openings, respectively. The filter elements separate a raw side inside the air conducting hose from a clean side downstream of the filter element. The air conducting hose is inflated in operation of the device by the air flow. The flexible air conducting hose has a reduced air permeability compared to the air permeability of the filter elements.

Abstract: A multi-modal multi-media air filtration system which can include: a base having one or more connection features and a filter media assembly, the filter media assembly being configured to attach to the base portion at a first end. The filter media assembly can then also include a first filter media extending across a first air flow path and a second filter media extending across a second air flow path. The air filtration assembly can then also include an actuation assembly configured to selectively open or close one of the first air flow path or the second air flow path so as to alternate the degree of filtration passing through the filter media assembly based on the degree of filtration provided by the first or second filter media.

Abstract: A filter device for ambient air filtration has a blower housing with air inlet and air outlet. A device for generating an air flow is arranged in the blower housing and generates an air flow in operation from air inlet to air outlet. A flexible air conducting hose is provided with a first open end connected to the air outlet of the blower housing and with a second closed end. The flexible air conducting hose has openings arranged between first open end and second closed end. Filter elements are arranged in the openings, respectively. The filter elements separate a raw side inside the air conducting hose from a clean side downstream of the filter element. The air conducting hose is inflated in operation of the device by the air flow. The flexible air conducting hose has a reduced air permeability compared to the air permeability of the filter elements.