The present application relates to an adsorption filter apparatus (30) for a vehicle heating, ventilation and air-conditioning, HVAC, system (20). The apparatus has an adsorption filter (51) configured to adsorb gaseous pollutants from an air flow through the apparatus; and an oxidant generator (40). The oxidant generator provides oxidants to flow in the air flow through the apparatus to cause active decomposition in the adsorption filter of the adsorbed gaseous pollutants retained by the adsorption filter (51). The present application also relates to a HVAC system (20), to a vehicle (10) having a HVAC system (20) and to a method of cleansing an adsorption filter apparatus for a vehicle HVAC system (20). The present application relates to a filter apparatus that uses an adsorption filter to take pollutants from an air flow in a HVAC system, and an oxidant generator to provide oxidants to the adsorption filter and to cleanse the adsorption filter of adsorbed pollutants.