A filter apparatus and method having a test port member in combination with a filter media. The test port member may be positioned adjacent the outer periphery of the outer peripheral frame and may be attached to a truncated portion of the filter media. One or more scrim layers may be disposed across one or more sides of the test port member and/or the truncated portion of the filter media. A plug may be inserted into a through port of the test port member.

A nitric oxide generator generates nitric oxide from a mixture of nitrogen and oxygen such as air treated by a pulsating electrical discharge. The desired concentration of nitric oxide is obtained by controlling at least one of a frequency of the pulsating electrical discharge and duration of each electrical discharge pulse.

A nitric oxide generator generates nitric oxide from a mixture of nitrogen and oxygen such as air treated by a pulsating electrical discharge. The desired concentration of nitric oxide is obtained by controlling at least one of a frequency of the pulsating electrical discharge and duration of each electrical discharge pulse.

A filter element assembly includes a filter body and an auxiliary filter. The filter body includes a sidewall around a hollow core. Further the filter body and auxiliary filter are both received and held on a support including a base and a cage.

An air cleaning system can rapidly senses occurrence of local pollution, caused by fine dust, through a remote sensor hub and supplies purified air to a polluted area in a concentrated manner, thereby quickly purifying indoor air.

A nitric oxide generator generates nitric oxide from a mixture of nitrogen and oxygen such as air treated by a pulsating electrical discharge. The desired concentration of nitric oxide is obtained by controlling at least one of a frequency of the pulsating electrical discharge and duration of each electrical discharge pulse.

A nitric oxide generator generates nitric oxide from a mixture of nitrogen and oxygen such as air treated by a pulsating electrical discharge. The desired concentration of nitric oxide is obtained by controlling at least one of a frequency of the pulsating electrical discharge and duration of each electrical discharge pulse.

A filter element assembly includes a filter body and an auxiliary filter. The filter body includes a sidewall around a hollow core. Further the filter body and auxiliary filter are both received and held on a support including a base and a cage.

An system includes a fabric filter, an air supply system, a pulsing valve that is coupled to the air supply system and is configured to generate a statistical pulse of air that is directed to the fabric filter, an air flow monitor that is configured to monitor a flow of air associated with the statistical pulse of air, and a valve controller that is coupled to the air flow monitor that is configured to generate a performance signature for the pulsing valve based on the flow of air that was monitored.

According to the present disclosure, air cleaner assemblies, housings, serviceable filter cartridges and features, components, and methods, relating thereto are disclosed. In general, the features relate to systems that are configured to aid in inhibiting an improper cartridge from being installed in an air cleaner housing, during servicing. A variety of features are characterized, and in many examples, the cartridge includes a seal arrangement having radially directed seal surface with at least a first non-wavy or non-projection/recess section and a second wavy or projection/recess section. Examples are shown and described in detail.