A gas cleaning system includes an inlet receiving a gas, an outlet spaced apart from the inlet, a gas channel defined between the inlet and the outlet to direct the gas from the inlet to the outlet, a photoionizer disposed to emit radiation towards a portion of the gas channel, and a first electrode module. The first electrode module includes a first discharge electrode assembly that generates a corona discharge within the gas channel and a first collection electrode assembly that collects ionized particles from the gas in the gas channel.

Filter media for an active field polarized media air cleaner includes two layers of dielectric material with a higher resistance air permeable screen sandwiched between the lower resistivity electric layers. The filter media may further include a mixed fiber filter layer having fibers from different sides of the triboelectric scale. The filter media may further include a layer of relatively higher density dielectric material followed by a layer of relatively lower density dielectric material.

Filter media for an active field polarized media air cleaner includes two layers of dielectric material with a higher resistance air permeable screen sandwiched between the lower resistivity electric layers. The filter media may further include a mixed fiber filter layer having fibers from different sides of the triboelectric scale. The filter media may further include a layer of relatively higher density dielectric material followed by a layer of relatively lower density dielectric material.

Examples are disclosed that relate to cooking systems with internal ventilation systems. One example provides a cooking system comprising a cooking appliance, a ventilation duct comprising an inlet aperture configured to receive cooking exhaust, a fan disposed within the ventilation duct, the fan being configured to pull the cooking exhaust through the inlet aperture and the ventilation duct, a particulate removal system positioned within the ventilation duct between the inlet aperture and the fan, and a grease containment pan disposed beneath the particulate removal system and comprising a mount for supporting the particulate removal system, the grease containment pan being removable from the ventilation duct by a user for cleaning.

Provided herein are methods of capturing particulates. The methods may include contacting particulates in a gas stream with one or more acoustic waves. The one or more acoustic waves may include standing waves or waves of modulating frequency. The methods may include promoting agglomeration of particulates with an electrostatic force. Also provided herein are systems for capturing particulates.

An air cleaning apparatus includes: a collection filter for collecting dust; a first ultraviolet light emitter for irradiating the collection filter with ultraviolet light having a first wavelength; and a photocatalyst supporting filter which supports a photocatalyst exhibiting photocatalytic activity by the ultraviolet light having the first wavelength and collects the dust. The collection filter transmits the ultraviolet light having the first wavelength, and the ultraviolet light having the first wavelength passing through the collection filter is irradiated to the photocatalyst supporting filter.

A particle detection element used to detect the number of particles in a gas includes: a casing having a gas flow passage through which the gas passes; an electric charge generating unit that imparts charges generated by a discharge to the particles in the gas introduced into the casing to thereby form charged particles; and a collecting unit including a collecting electrode that is disposed inside the casing and collects a collection target that is the charged particles or the charges not imparted to the particles. The casing has a reinforcing portion on at least one of an outer circumferential surface and an inner circumferential surface of the casing, and the reinforcing portion partially thickens a wall of the gas flow passage.

This publication discloses an electrostatic filter construction, to be positioned in air ducts or ventilation channels, which electrostatic filter construction includes a charging unit, which charges the particles to be filtered into a first electric potential and arranged in the filter construction in the path of the air flow before filter elements, electrically conducting electrodes connected to a second electric potential different to the potential of the charged particles and set substantially parallel to the direction of the airflow, and bag shaped filter elements positioned after the charging unit in the path of the air flow. According to the invention each bag shaped filter element has at least one designated UV-light source and an element of photo catalytic material like TiO.sub.2.

A particle counter includes a ventilation path, an electric-charge generator that applies the electric charge to a particle in the gas that passes through the ventilation path to obtain a charged particle, a charged-particle-collecting electrode, a heater that is capable of heating the ventilation path, and a controller for performing a particle count detection process, wherein, when the process is performed, the controller obtains a flow rate of the gas on the basis of a calorific value that is supplied to the heater and a difference between the temperature of the gas and the temperature of the surface of the heater, with the heater heating the ventilation path, and obtains the count of the particle per unit volume in the gas on the basis of the flow rate of the gas and a physical quantity that varies depending on an electric charge amount of the charged particle.

This publication discloses a filter unit connectable to a mobile communication device including a fan for generating an air flow inside the filter unit, electrodes covered with a photo catalytic material like TiO.sub.2 in the air flow, UV-LEDs illuminating the electrodes, and outlet for the air flow directed in direction of user of filter unit.