We claim:
1. A cartridge media for removing various types of pollutants from an
airstream, comprising:
a first mesh filter(lOl) intended to exclude coarse particles of size 15 microns or greater;
a second chemical layer(103) configured to remove CO2 from the airstream
a third layer(105) comprising an adsorbent configured to remove a chemical pollutant or
an oxidizing chemical substance configured to remove a biological contaminant, or both;
and
a fourth fibrous filter layer configured to filter particulate pollutants in the range 0.3-10
microns.
2. The cartridge media of claim 1, wherein the adsorbent media in the third layer(105) comprises activated charcoal and the oxidizing chemical substance comprises one or more of KMn04 or KOH.
3. The cartridge media of claim 2, wherein the activated charcoal is impregnated with the KMn04 or KOH.
4. The cartridge media of claim 1, wherein the chemical layer(103) comprises hydrated lime (Ca(OH)2).
5. The cartridge media of claim 4, wherein the hydrated lime is impregnated with one of potassium hydroxide, or sodium hydroxide.
6. The cartridge media of claim 1, wherein the cartridge is shaped as a hollow section configured to purify air from the exterior thereof into an annular portion of the cartridge.

7. An air purification system comprising the filter cartridge of claim 6,
comprising:
an enclosure with air inlets to allow air to be drawn into the filter cartridge;
a motor and fan arrangement configured to run at variable speeds and draw air from the
annular portion of the filter cartridge; and
a control unit configured to operate the system at selected speeds to effect removal of a
pollutant selected from one or more of volatile organic compounds, CO2 or particulate
matter.