HEPA - High Efficiency Particulate Air : Filter captures 99.97% of airborne pollution, allergens, smoke and odours, which can cause breathing difficulties. The HEPA Filter has 5 stages to purify and revitalise the air. Stage 1 Pre-Filter: Collects larger-sized particles in the air such as pollen and hair. Stage 2 Multi Filter Cartridges (2) Multi Filters (white): Remove 99.97% of airborne particles 0.3 micron or larger. Stage 3 Multi-catalist filters (grey): Absorb and decompose odours. Stage 4 Active Carbon Filters (black): Remove smoke and odour. Stage 5 Ioniser: Release negative ions to remove airbourne contaminants (such as smog, pollen and dust). Stage 1 Pre-Filter: Pre-Filter collects larger-sized particles in the air such as pollen and hair. Stage 2 Multi Filter .