Air filtration device

An air filtration cartridge suitable for use in the treatment of air in a forced airflow air supply system having an air supply conduit provided with an in-line filtration cartridge mounting formed and arranged for releasably mounting a replaceable air filtration cartridge so that the air supply is passed through said cartridge, said cartridge comprising a casing having:

• an upstream stage defining a chamber, the chamber being defined by an earthed casing comprising a metal or a plastics material impregnated or coated with a metallic material and having an inlet for receiving a said forced airflow, in use of the cartridge, and an outlet;
• at least one low power coronal discharge ozone generator mounted inside the chamber, said at least one ozone generator being formed and arranged for generating a restricted concentration of ozone and any other reactive species formed together therewith, within an inactivating zone contained within said cartridge, through which said air flow is passed in use of said cartridge, which restricted concentration is sufficient to effectively inactivate airborne pollutant material entrained in the air flow, yet which restricted concentration decays sufficiently outside said inactivating zone so that the concentration of ozone in the cleaned air expelled from said cartridge is at a physiologically acceptable level without the use of an ozone decomposition catalyzer;
• and
• a downstream stage coupled to said upstream stage outlet and formed and arranged for mounting, in use of the cartridge, a high airflow electrostatic filter.