FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
TITLE OF THE INVENTION AN ADSORPTION FILTER APPARATUS FOR A VEHICLE HVAC SYSTEM
APPLICANT
1) TATA MOTORS LIMITED
An Indian company
having its registered office at
Bombay House, 24 HomiMody Street,
Hutatma Chowk, Mumbai 400001,
Maharashtra, India
And
2) TATA MOTORS EUROPEAN TECHNICAL CENTRE PLC,
18 Grosvenor Place, London, SW1X7HS,
London, United Kingdom, Nationality United Kingdom
INVENTORS
STIEHLER, Daniela An German Nationals of
Tata Motors European Technical Centre Plc, International
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the
manner in which it is to be performed

FIELD OF INVENTION
The present disclosure relates to an adsorption filter apparatus for a vehicle heating, ventilation and air-conditioning (HVAC) system. Aspects of the invention relate to an adsorption filter apparatus, to a HVAC system, to a vehicle having a HVAC system and to a method of cleansing an adsorption filter apparatus for a vehicle HVAC system.
BACKGROUND OF THE INVENTION
There is an urgent need to improve the capabilities of the odour and gaseous pollutant removal performance of a cabin air filter for a vehicle.
Cabin air filters for vehicle heating, ventilation and air-conditioning (HVAC) system are used to protect the system itself as well as passengers in the vehicle.
Cabin air filters typically include a particulate filter to remove particulates in air passing through a HVAC system and a gas cleaning filter to clean the air flow of gaseous pollutants. One such gas cleaning filter includes activated carbon. With such a gas cleaning filter, gaseous inorganic and organic substances are adsorbed by the activated carbon and are retained the gas cleaning filter.
Gas cleaning filters using activated carbon have a limited adsorption capacity. Once the activated carbon has reached adsorption capacity, the filter can become ineffective. The high air pollution levels found in some parts of the world can lead to a fast overload of the adsorption capacity of the gas cleaning filter. Although overloading the gas cleaning filter does not have an effect on the air flow performance of the HVAC system, it does mean that further gaseous pollutants pass through the gas cleaning filter without being adsorbed. Furthermore, the activated carbon can go into a desorption state in which odours and pollutant gases are released from the filter back into the air flow. Such desorption is increased in hot and/or humid conditions.
At least in certain embodiments, the present invention seeks to overcome or ameliorate at least some of the shortcomings associated with the prior art.

SUMMARY OF THE INVENTION
Aspects and embodiments of the invention provide an adsorption filter apparatus, a HVAC system, a vehicle having a HVAC system and a method of cleansing an adsorption filter apparatus for a vehicle HVAC system as claimed in the appended claims.
According to an aspect of the invention, there is provided an adsorption filter apparatus for a vehicle heating, ventilation and air-conditioning, HVAC, system, the apparatus comprising an adsorption filter configured to adsorb gaseous pollutants from an air flow through the apparatus; and an oxidant generator, wherein the oxidant generator is configured to provide 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.
The oxidant generator may be disposed adjacent to the adsorption filter.
The oxidant generator may be disposed to provide oxidants in the air flow immediately upstream of the adsorption filter.
The oxidant generator may be spaced less than 40mm, and optionally less than 30mm, and further optionally less than 25mm from the adsorption filter.
The spacing between the oxidant generator and the adsorption filter may be measured along an air flow pathway. This may allow for embodiments where the air flow changes direction, for example the air flow pathway is folded.
The adsorption filter may comprise a molecular sieve.
The molecular sieve may comprise activated carbon.
The molecular sieve may consist of activated carbon.

The adsorption filter comprises an upstream side, and the oxidant generator extends across the upstream side of the adsorption filter.
The adsorption filter apparatus may comprise a duct along which the air flow through the apparatus passes.
The duct may comprise at least part of a HVAC blower - filter labyrinth.
The oxidant generator may extend across the duct.
The duct may comprise at least part of a HVAC blower - filter labyrinth; the oxidant generator may extend across a cross-section of said HVAC blower - filter labyrinth.
The oxidant generator may comprise a conductive mesh.
The oxidant generator may comprise a plurality of electrical discharge points on the conductive mesh.
The conductive mesh may comprise a plurality of peaks protruding from the conductive mesh.
Each peak may define an electrical discharge point.
One or more peak may face the adsorption filter.
Each peak may face the adsorption filter.
The adsorption filter apparatus may comprise an electrical charge supply configured to supply an electrical charge to the conductive mesh.
A spacer may be disposed between the adsorption filter and the oxidant generator.
The spacer may comprise at least one of an air gap and a particle filter.

The particle filter and adsorption filter may together form a filter module.
The filter module may comprise a support.
The oxidants may include at least one selected from a group comprising oxygen and hydroxyl
character radicals and ozone.
The adsorption filter may be configured to provide a chemical reaction zone in which substantially all oxidants provided by the oxidant generator react.
The adsorption filter may be configured to retain oxidants for a time period sufficient to ensure that substantially all oxidants react with adsorbed gaseous pollutants to form water and carbon dioxide.
According to another aspect of the invention, there is provided a heating, ventilation and air-conditioning, HVAC, system for a vehicle comprising an adsorption filter apparatus as described above.
The heating, ventilation and air-conditioning, HVAC, system may comprise an evaporator downstream of the adsorption filter configured to recombine oxidants passing from the adsorption filter.
The heating, ventilation and air-conditioning, HVAC, system may comprise a sensor configured to determine the presence of oxidants downstream of the adsorption filter.
According to another aspect of the invention, there is provided a vehicle comprising an adsorption filter apparatus or a HVAC system as described above.
According to another aspect of the invention, there is provided a method of cleansing an adsorption filter apparatus for a vehicle heating, ventilation and air-conditioning, HVAC, system, the method comprising providing an adsorption filter configured to adsorb gaseous pollutants from an air flow through the apparatus; providing 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.
According to an aspect of the invention, there is provided an adsorption filter apparatus for a vehicle heating, ventilation and air-conditioning, HVAC, system, the apparatus comprising an adsorption filter configured to adsorb gaseous pollutants from a fluid flow through the apparatus; and an oxidant generator. Typically, the fluid comprises air and the adsorption filter is configured to adsorb gaseous pollutants from the air flowing through the apparatus.
Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.
BRIEF DESCRIPTION OF THE DRAWINGS
One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a view of a vehicle according to an embodiment of the invention; Figure 2 is a schematic cross-sectional, side view of part of a heating, ventilation and air-conditioning (HVAC) system according to an embodiment of the invention; Figure 3 is a schematic cross-sectional, side view of a filter module of the HVAC system of Figure 2;
Figure 4 is a schematic cross-sectional, side view of part of a HVAC system according to another embodiment of the invention;
Figure 5 is a schematic view of an oxidant generator of the HVAC system of Figure 2 from a downstream side;

Figure 6 is a schematic side view of the oxidant generator of Figure 5; and Figure 7 is a schematic view of part of the adsorption filter apparatus.
DETAILED DESCRIPTION
A vehicle 10 is shown in Figure 1. The vehicle 10 shown is an automobile, although the type of vehicle is not limited thereto. The vehicle 10 comprises a vehicle front end 11. The vehicle has a heating, ventilation and air conditioning system (HVAC) 20. The HVAC system 20 is disposed in the vehicle 10 and provides heating, ventilation and air conditioning to an interior space 12 of the vehicle 10. The interior space 12 is typically arranged to receive one or more occupants.
The HVAC system 20 is shown in more detail in Figure 2. The HVAC system 20 comprises a flow path 21 along which air flows. The air passes along the flow path 21 from an inlet 22 to an outlet 23. The inlet 22 is open to the external atmosphere around the vehicle 10, and the outlet 23 vents to the interior space 12. However, alternative arrangements are possible. A fan 24, acting as an air flow means, is disposed along the flow path 21. The fan 24 acts to move air along the flow path 21. In the present embodiment the fan 24 is proximate to the inlet 22. In embodiments, the HVAC system has a recirculation configuration in which the inlet 22 and outlet 23 are open to the interior space 12.
An evaporator 25 is disposed in the flow path 21. The evaporator 25 is disposed so that air flowing along the flow path 21 flows through the evaporator 25 prior to flowing through the outlet 23.
The HVAC system 20 comprises an adsorption filter apparatus 30. The adsorption filter apparatus 30 is disposed along the flow path 21. A duct 31 defines part of the flow path 21 at the adsorption filter apparatus 30. The adsorption filter apparatus 30 is configured to remove gaseous pollutants from the air flowing through the HVAC system 20.
The adsorption filter apparatus 30 is disposed upstream of the evaporator 25. With air flowing from the inlet 22 to the outlet 23, upstream is defined as on an inlet side of the air flow relative to another feature, and downstream is defined as on an outlet side of the air flow

relative to another feature. The adsorption filter apparatus 30 is spaced from the evaporator
25.
Referring to Figure 3, the adsorption filter apparatus 30 comprises a filter module 50 and an oxidant generator 40. The filter module 50 has an adsorption filter 51 and a particle filter 52. The adsorption filter 51 and the particle filter 52 are disposed in series in the flow path 21. The particle filter 52 is disposed upstream of the adsorption filter 51. In the present embodiment, the particle filter 52 abuts the adsorption filter 51. The particle filter 52 may be omitted, or may be disposed elsewhere along the flow path 21.
The filter module 50 also includes a support 53. The support 53 provides stability to the adsorption filter 51. In one embodiment the adsorption filter 51, particulate filter 52 and support 53 are integrally formed. The adsorption filter 51 may be an adsorption filter layer. The particle filter 52 may be a particle filter layer. The support 53 may be a support layer. The filter module 50 in such a configuration is a combined cabin air filter. In one embodiment the filter module 50 has a pleated configuration.
The support 53 may be omitted. The adsorption filter 51 is disposed between the particle filter 52 and the support 53 in the present embodiment. The support 53 retains the adsorption filter 51 in the duct 31, although alternative retention means may be used. The support 53 may provide a coating surface for the activated carbon granulate.
The particle filter 52 is configured to filter particulates carried in the air flow. The particle filter 52 extends across the flow path 21. That is, the particle filter 52 is configured so that all air flowing along the flow path 21 flows through the particle filter 52. The particle filter 52 comprises fibres in a non-woven arrangement. The fibres in one embodiment are glass fibres. The particle filter 52 may comprise filter sections of differing coarseness to filter different sizes of particulate.
The adsorption filter 51 is configured to adsorb gaseous pollutants in the air flow. The adsorption filter 51 extends across the flow path 21. That is, the adsorption filter 51 is configured so that all air flowing along the flow path 21 flows through the adsorption filter 51. The adsorption filter 51 is bounded by the duct 31. The adsorption filter 51 comprises

activated carbon 54. The activated carbon 54 acts as a molecular sieve. Alternative materials may be used as a molecular sieve in place of or together with activated carbon 54, such materials include other adsorptive media such as zeolites.
Pathways are defined in the adsorption filter 51. Such pathways are defined, at least in part, by pores in the activated carbon 54. The activated carbon 54 adsorbs gaseous pollutants such that the pollutants are retained on the surface of the pores of the activated carbon 54. Gaseous organic substances in the air flow are adsorbed via chemisorption. The gaseous pollutions are retained by the adsorption filter 51.
The adsorption filter 51 has an upstream side 55 and a downstream side 56. Air flows into the adsorption filter 51 through the upstream side 55 and flows from the adsorption filter 51 through the downstream side 56.
The oxidant generator 40 is configured to provide oxidants to flow in the air flow. The oxidant generator 40 provides oxidants which include at least one selected from the group comprising oxygen and hydroxyl character radicals, and ozone. The oxidants are used to react with pollutants in the pores of the activated carbon to provide a cleansing effect, as will be explained in detail below. In the present embodiment, the oxidant generator 40 is configured to generate oxidants from the air flow flowing along the flow path 21. In particular, oxygen becomes singlet activated Oxygen (O) radicals or Ozone (O3), and water molecules are split into hydroxyl radicals (*OH). Such oxidants are non-selectively reactive with organic gaseous pollutions. The oxidant generator 40 is configured to produce chemical radicals, for example oxygen and hydroxyl radicals, with a high oxidation potential. Such chemical radicals have a higher oxidation potential than ozone. The use of substances with a higher oxidation potential increases the cleansing ability of the system. Ozone is also produced. The produced ozone is used as reference oxidant to evaluate the productivity of the generator.
Referring to Figs. 5 and 6, the oxidant generator 40 comprises a conductive mesh 41. The conductive mesh 41 comprises a wire mesh 42. As such, the conductive mesh 41 has a grid arrangement with electrical conduit portions 43 defining a plurality of apertures 44 there-between. The conductive mesh 41 extends across the flow path 21. Air flowing along the air path 21 therefore flows through the conductive mesh 41. The apertures 44 have an opening

size of 500 to 2000 nanometres. The conductive mesh 41 is formed, for example, from stainless steel.
The conductive mesh 41 has a planar configuration. However, alternative configurations are possible. The conductive mesh 41 extends substantially parallel to an upstream side 55 of the adsorption filter 51.
The conductive mesh 41 has needles 45 protruding from the conduit portions 43. The needles 45 act as peaks on the conductive mesh 41. Each needle 45 has a free end 46 which extends to a point. The needles 45 are formed at junctures of the grid arrangement. Each juncture has one or more needles defined protruding from the juncture. However, the distribution of needles 45 may vary. Each free end 46 acts as an electrical discharge point at which oxidants are formed in the air flowing past the needles 45. Each needle 45 extends perpendicular to a plane of the conductive mesh 41. The needles 45 are configured to extend in a downstream direction. As such, the free ends 46 of the needles 45 extend towards the adsorption filter 51.
A potential gradient is generated when an electrical charge is provided to the conductive mesh 41. The electrical charge is configured to ensure that the potential gradient is large enough at the free ends 46 such that the fluid at that point ionises and becomes conductive. As such, oxidants are produced. A power supply 80, acting as an electrical charge supply, provides an electrical charge to the conductive mesh 41. A control module 70 in the form of a processor operates the power supply 80 to control operation of the oxidant generator 40.
The needles 45 are formed in a grid arrangement and are spaced across the conductive mesh 41. The oxidant generator 40 extends across the flow path 21. That is, the adsorption filter 51 is configured so that all air flowing along the flow path 21 flows through the oxidant generator 40. The oxidant generator 40 is disposed in series with the adsorption filter 51 in the flow path. The needles 45, acting as electrical discharge points, are distributed across the flow path 21. As such, there are electrical discharge points distributed across the flow path 21. During operation, oxidants are generated across the flow area of the flow path 21. Air flow exiting from the oxidant generator 40 therefore has oxidants distributed across the flow area.

The oxidant generator 40 is disposed adjacent to the adsorption filter 51. That is, the oxidant generator 40 is in close proximity, but not necessarily in abutment with, the adsorption filter 51. Indeed, in some embodiments (notably those illustrated in Figs. 3 and 4) a particle filter 52 may be disposed between the oxidant generator 40 and the adsorption filter 51 while still maintaining the arrangement of the oxidant generator 40 in close proximity with the adsorption filter 51. The oxidant generator 40 is disposed to provide oxidants in the air flow immediately upstream of the adsorption filter 51. In the present arrangement, the oxidant generator 40 is spaced less than 40mm from the adsorption filter. The spacing may be less than 30mm, and less than 25mm.
A gap 32 is defined between the oxidant generator 40 and the upstream side 55 of the adsorption filter 51. The gap 32 ensures that the oxidant generator 40 is conductively isolated from the activated carbon 54. Due to the arrangement of the oxidant generator 40, which is configured to produce oxidants across the flow area of the flow path 21, it is possible to minimise a spacing between the oxidant generator 40 and the adsorption filter 51. Oxidants have a limited lifecycle. As such, a greater concentration of oxidants are able to flow into the adsorption filter 51 when the spacing between the oxidant generator 40 and the adsorption filter 51 is minimised. This increases the effectiveness of the cleansing of the adsorption filter 51.
As the oxidants are distributed throughout the air flow flowing from the oxidant generator 40 mixing is not required to ensure that homogenous mixing occurs prior to the air flow entering the adsorption filter 51. Furthermore, the surfaces in which the oxidants may come into contact prior to entering the adsorption filter 51 are minimised. As such, the efficiency of the adsorption filter apparatus 30 is maximised.
It will be understood that the particle filter 52 may act as a spacer between the oxidant generator 40 and the upstream side 55 of the adsorption filter 51. Alternatively or in addition to the spacer, there may be an air gap between the oxidant generator 40 and the upstream side 55 of the adsorption filter 51. As shown in Figure 2, the gap 32 between the oxidant generator 40 and the upstream side 55 of the adsorption filter 51 is defined by an air gap acting as a spacer. In Figure 4, the gap 32 is defined by part of the filter module 50. In this embodiment, the particle filter 52 acts as the spacer.

Air flowing along the flow path 21 from the inlet 22 includes gaseous pollutants. The air is drawn along the flow path 21 by the fan 24. Downstream from the fan 24, the air flows along the duct 31 into the oxidant generator 40. As described above, the oxidants generated by the oxidant generator 40 are entrained into the air flow, and dispersed across the flow area. That is, at least substantially the whole of the cross sectional area of the duct. The air flow containing gaseous pollutants and oxidants substantially immediately enters the upstream side of the adsorption filter 51. A small quantity of oxidants may react with gaseous pollutants in the air flow.
The gaseous pollutants passing into the adsorption filter 51 are adsorbed in the pores of the activated carbon 54 and so are retained in the filter. As such, the adsorbed pollutants are prevented from flowing from the downstream side 56 of the adsorption filter 51.
The oxidants, including at least one selected from the group comprising oxygen and hydroxyl character radicals, and ozone, generated by the oxidant generator 40, flow in the air flow to the adsorption filter 51. Upon entering the adsorption filter 51, the oxidants acting as reactive substances, react with the adsorbed gaseous pollutants retained by the adsorption filter 51 and cause active decomposition in the adsorption filter 51 of the adsorbed gaseous pollutants retained by the adsorption filter 51. The adsorption filter 51 acts as a chemical reaction zone in which the oxidants non-selectively react with organic and non-organic adsorbed pollutants. Substantially all oxidants provided by the oxidant generator 40 react with the adsorbed pollutants.
As the adsorption filter 51 retains gaseous pollutants, it provides a time period (a dwell time) sufficient to ensure that substantially all oxidants and organic gaseous pollutants passing into the adsorption filter react to form water and carbon dioxide by active decomposition. The oxidants, such as singlet activated Oxygen (O), Ozone (O3) and hydroxyl radicals (*OH), react with organic gaseous pollutants and adsorbed pollutants in the pores of the activated carbon 54. These reactions produce oxidation by-products which then further react with oxidants. Such processes result in the mineralisation of the contaminants to carbon dioxide and water through active decomposition. Accordingly, the gaseous pollutants are effectively extracted from the air flow and do not flow through the outlet 23. Furthermore, the adsorption

filter is actively cleansed through active decomposition of the adsorbed pollutants and so does not become saturated with adsorbed pollutants, or reach or exceed adsorption capacity.
In one embodiment, the oxidation production rate should be between 30-60 mg ozone/hour with a power consumption about 500mA under an operating voltage between 9-16 Volts DC.
The air flow passing from the downstream side 56 of the adsorption filter 51 contains the end-products of the reactions. Typically the dwell time within the adsorption filter 51 ensures that all oxidants flowing into the adsorption filter 51 react within the adsorption filter 51. Active substances, for example intermediate products such as organic radicals produced by previous reactions, in the adsorption device react with further oxidants or other organic radicals to produce further reactions. Organic radicals are adsorbed by the adsorption filter to promote further reactions.
Oxidants and other active substances flowing from the adsorption filter 51 flow further along the flow path to the evaporator 25. Remaining oxidants and active substances will then recombine at the evaporator 25. This helps to ensure that remaining oxidants and active substances do not flow through the outlet 23 of the flow path 21.
As illustrated in Figure 7, in one embodiment a sensor 60 is disposed downstream of the adsorption filter 51. In the embodiment of Figure 2, a mixing chamber 34 is disposed downstream of the evaporator 25. The sensor 60 is disposed in the mixing chamber 34. The sensor 60 is configured to detect the presence and quantity / concentration of ozone in the air flow. The presence and quantity / concentration of other oxidants (e.g. oxygen radicals, hydroxyl radicals) may be determined by reference to the presence and quantity / concentration of the detected ozone in combination with a knowledge of a ratio in which the oxidant generator produces different types or species of oxidants. Alternatively, or in addition, other types or species of oxidants and/or active substances may be detected directly by the sensor 60. The control module 70 is configured to refer to the sensor 60 to determine the presence of oxidants and/or active substances. In the event that it is determined that oxidants and/or active substances are present then the control module 70 is configured to adjust operation of the oxidant generator 40, for example by reducing or stopping the supply of electrical charge to the oxidant generator 40 by the power supply 80.

Although one configuration of the oxidant generator 40 is described above, it will be understood that alternative configurations of oxidant generator 40 may be used. In the above described embodiment, the oxidants are generated by corona discharge, that is when the potential gradient (electrical field) is large enough at a point in the fluid (alternatively referred to herein as air) that the fluid at that point ionises and becomes conductive. However, it will be understood that other oxidant generation means may be used. The oxidant generator may be a dielectric discharge device.
It will be understood that urban areas in regions of high humidity and temperature often have high concentrations of pollutants in the atmosphere. As such, in high humidity the concentration of hydroxyl character radicals is increased, and is able to react with the greater number of pollutants in such regions. Therefore, the apparatus has a degree of self-regulation during operation.
In the above described embodiments, the oxidant generator 40 is used continuously during operation of the HVAC system 20. However, it will be understood that the oxidant generator 40 may be used intermittently. In such an operating condition, the adsorption filter 51 prevents the flow of pollutants to the outlet 34 by adsorbing the gaseous pollutants irrespective of the operating condition of the oxidant generator 40. The oxidant generator 40 is operated to cleanse the adsorption filter 51 such that the adsorption filter 51 does not become saturated with adsorbed pollutants, or reach or exceed adsorption capacity.
Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the invention as claimed.
Features described in the preceding description may be used in combinations other than the combinations explicitly described.
Although functions have been described with reference to certain features, those functions may be performable by other features, whether described or not.

Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not.
Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance, it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings, whether or not particular emphasis has been placed thereon.

WE CLAIMS
1. An adsorption filter apparatus (30) for a vehicle heating, ventilation and air-
conditioning, HVAC, system (20), the apparatus comprising:
an adsorption filter (51) configured to adsorb gaseous pollutants from an air flow through the apparatus; and
an oxidant generator (40);
wherein:
the oxidant generator is configured to provide 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.
2. The adsorption filter apparatus of claim 1, wherein the oxidant generator (40) is disposed adjacent to the adsorption filter (51).
3. The adsorption filter apparatus of claim 2, wherein the oxidant generator (40) is disposed to provide oxidants in the air flow immediately upstream of the adsorption filter (51).
4. The adsorption filter apparatus of claim 2 or claim 3, wherein the oxidant generator (40) is spaced less than 40mm, and optionally less than 30mm, and further optionally less than 25mm from the adsorption filter (51).
5. The adsorption filter apparatus of any one of the preceding claims, wherein the adsorption filter (51) comprises a molecular sieve.
6. The adsorption filter apparatus of claim 5, wherein the molecular sieve comprises activated carbon.
7. The adsorption filter apparatus of any preceding claim, wherein the adsorption filter (51) comprises an upstream side (55), and the oxidant generator (40) extends across the upstream side of the adsorption filter.

8. The adsorption filter apparatus of any preceding claim, comprising a duct (31) along which the air flow through the apparatus passes.
9. The adsorption filter apparatus of any preceding claim, wherein the oxidant generator (40) extends across the duct (31).
10. The adsorption filter apparatus of any preceding claim, wherein the oxidant generator (40) comprises a conductive mesh (41).
11. The adsorption filter apparatus of claim 10, wherein the oxidant generator (40) comprises a plurality of electrical discharge points on the conductive mesh (41).
12. The adsorption filter apparatus of claim 11, wherein the conductive mesh comprises a plurality of peaks (46) protruding from the conductive mesh, wherein each peak defines an electrical discharge point.
13. The adsorption filter apparatus of claim 12, wherein one or more peak (46) faces the adsorption filter (51).
14. The adsorption filter apparatus of any preceding claim, comprising an electrical charge supply (80) configured to supply an electrical charge to the conductive mesh (41).
15. The adsorption filter apparatus of any preceding claim, wherein a spacer is disposed between the adsorption filter (51) and the oxidant generator (40).
16. The adsorption filter apparatus of claim 15, wherein the spacer comprises at least one of an air gap and a particle filter (52).
17. The adsorption filter apparatus of claim 16, wherein the particle filter (52) and adsorption filter (51) together form a filter module (50).
18. The adsorption filter apparatus of claim 17, wherein the filter module (50) comprises a support (53).

19. The adsorption filter apparatus of any preceding claim, wherein the oxidants include at least one selected from a group comprising oxygen and hydroxyl character radicals and ozone.
20. The adsorption filter apparatus of any preceding claim, wherein the adsorption filter (51) is configured to provide a chemical reaction zone in which substantially all oxidants provided by the oxidant generator (40) react.
21. The adsorption filter apparatus of claim 20, wherein the adsorption filter (51) is configured to retain oxidants for a time period sufficient to ensure that substantially all oxidants react with adsorbed gaseous pollutants to form water and carbon dioxide.
22. A heating, ventilation and air-conditioning, HVAC, system (20) for a vehicle (10) comprising an adsorption filter apparatus (30) of any preceding claim.
23. The heating, ventilation and air-conditioning, HVAC, system of claim 22, comprising an evaporator (25) downstream of the adsorption filter (51) configured to recombine oxidants passing from the adsorption filter.
24. The heating, ventilation and air-conditioning, HVAC, system of claim 23, comprising a sensor (60) configured to determine the presence of oxidants downstream of the adsorption filter (41).
25. A vehicle (10) comprising an adsorption filter apparatus (30) of any one of claims 1 to 21 or a HVAC system (20) according to any one of claims 22 to 24.
26. A method of cleansing an adsorption filter apparatus (30) for a vehicle heating, ventilation and air-conditioning, HVAC, system (20), the method comprising:
providing an adsorption filter (51) configured to adsorb gaseous pollutants from an air flow through the apparatus;

providing 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.
27. An adsorption filter apparatus, a heating, ventilation and air-conditioning, HVAC, system, a vehicle, or a method of cleansing an adsorption filter apparatus substantially as described herein with reference to the accompanying drawings.