A general ventilation and air filtration system includes an air filtration control unit that monitors and controls an air flow through an air filter and maintains the air flow at a target velocity set point. The target velocity set point is maintained by monitoring and regulating the power of a motor powering a blower that generates an air flow through the air filtration system and through the air filter. By regulating the air flow and maintaining it in the target set point, power consumption and air filter life are significantly improved.

An air purifying device includes an air purifier mechanism, a controller, and a sensing device configured to detect one or more conditions in a predetermined area proximate the air purifying device. The controller is configured to receive an input to select one of the predetermined operational settings to govern the operation of the air purifier mechanism. The air purifier mechanism is configured to operate in at least one of a plurality of modes of operation in each of its predetermined operational setting. The controller is configured to change modes of operation of the air purifier mechanism from a first mode of operation to a second mode of operation in response to its sensing device detecting a change in said one or more conditions in the predetermined area and based on the selected predetermined operational setting.

An air purifying device includes an air purifier mechanism, a controller, and a sensing device configured to detect one or more conditions in a predetermined area proximate the air purifying device. The controller is configured to receive an input to select one of the predetermined operational settings to govern the operation of the air purifier mechanism. The air purifier mechanism is configured to operate in at least one of a plurality of modes of operation in each of its predetermined operational setting. The controller is configured to change modes of operation of the air purifier mechanism from a first mode of operation to a second mode of operation in response to its sensing device detecting a change in said one or more conditions in the predetermined area and based on the selected predetermined operational setting.

An integrated autonomous air purification device for taking in polluted air, carrying it through the inside of the purification device where it passes through a set of filtering elements (1) that trap the dust particles contained in the air; ultraviolet-light lamps (2) that transform NO.sub.X and CO gases in the air into harmless compounds; an activated carbon filter (4) that traps and eliminates the volatile organic compounds and inorganic acidic gases; second filtering elements (5) that carry out a second filtering; and an extraction hood (6) configured to direct the air coming out of the second filtering elements (5) to at least one nozzle (7) that expels the air to the outside of the purification device.

An integrated autonomous air purification device for taking in polluted air, carrying it through the inside of the purification device where it passes through a set of filtering elements (1) that trap the dust particles contained in the air; ultraviolet-light lamps (2) that transform NO.sub.X and CO gases in the air into harmless compounds; an activated carbon filter (4) that traps and eliminates the volatile organic compounds and inorganic acidic gases; second filtering elements (5) that carry out a second filtering; and an extraction hood (6) configured to direct the air coming out of the second filtering elements (5) to at least one nozzle (7) that expels the air to the outside of the purification device.

A refrigerator and an air purifier for a refrigerator are provided. The air purifier may include a case configured to be mounted on an upper surface of a cabinet of a refrigerator and in which inlet holes and an outlet hole are formed, a plurality of fan motor assemblies provided inside of the case to force a flow of air, a plurality of filter assemblies mounted in the case to partition a space between the inlet holes and the plurality of fan motor assemblies and purify suctioned air, a controller that controls driving of the plurality of fan motor assemblies, and a gas sensor connected to the controller to detect harmful gas in a kitchen space. The controller may control driving of the plurality of fan motor assemblies through detection of the harmful gas by the gas sensor.

An aftertreatment system comprises a SCR system, a first filter, and a second filter disposed downstream of the first filter and a bypass conduit providing a flow path bypassing the second filter. A valve is operatively coupled to the bypass conduit and is moveable between a closed position in which the exhaust gas flows through the second filter, and an open position in which at least a portion of the exhaust gas flows through the bypass conduit. A controller is operatively coupled to the valve configured to adjust the valve based on a first filtration efficiency of the first filter to cause the exhaust gas expelled into the environment from the aftertreatment to have a particulate matter count meeting particulate matter emission standards.

An aftertreatment system comprises a SCR system, a first filter, and a second filter disposed downstream of the first filter and a bypass conduit providing a flow path bypassing the second filter. A valve is operatively coupled to the bypass conduit and is moveable between a closed position in which the exhaust gas flows through the second filter, and an open position in which at least a portion of the exhaust gas flows through the bypass conduit. A controller is operatively coupled to the valve configured to adjust the valve based on a first filtration efficiency of the first filter to cause the exhaust gas expelled into the environment from the aftertreatment to have a particulate matter count meeting particulate matter emission standards.

An air purification device includes a device main body, a purification filter and a gas detection module. The device main body includes a gas-inlet opening and a gas-outlet opening. The purification filter is disposed in the device main body and includes at least one activated carbon layer and at least one zeolite layer stacked on each other, wherein the activated carbon layer filters and absorbs suspended particles contained in an air introduced through the gas-inlet opening, and the zeolite layer includes porous structures with hydrophobic property for controlling and absorbing volatile organic compounds contained in the air introduced through the gas-inlet opening, thereby a purified gas is generated from the air and is discharged through the gas-outlet opening. The gas detection module is disposed in the device main body for detecting and obtaining a gas quality data of the air passing through the gas-inlet opening and outputting the gas quality data.

An air purification device includes a device main body, a purification filter and a gas detection module. The device main body includes a gas-inlet opening and a gas-outlet opening. The purification filter is disposed in the device main body and includes at least one activated carbon layer and at least one zeolite layer stacked on each other, wherein the activated carbon layer filters and absorbs suspended particles contained in an air introduced through the gas-inlet opening, and the zeolite layer includes porous structures with hydrophobic property for controlling and absorbing volatile organic compounds contained in the air introduced through the gas-inlet opening, thereby a purified gas is generated from the air and is discharged through the gas-outlet opening. The gas detection module is disposed in the device main body for detecting and obtaining a gas quality data of the air passing through the gas-inlet opening and outputting the gas quality data.