HEPA - High Efficiency Particulate Air : Filter captures 99.97% of airborne pollution, allergens, smoke & odours, which can cause breathing difficulties. A HEPA filter has 5 stages

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 & decompose harmful gases such as ammonia & carbon monoxide
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).