4-stage purification system filters 99.97% of all airborne pollutants as small as 0.3 micrometres (viruses, allergens e.g. pollen, dust mites, mould spores, animal dander, cigarette smoke). Performance: 5 air changes/hour (room with 18m²) and 3 air flows/hour (room with 28m²). AeraSafe™ - the built-in antimicrobial protection prevents the accumulation of odour-causing bacteria, mould and fungi. AeraSmart™ sensor constantly monitors air... quality and automatically adjusts fan speed. Aera+™ mode increases airflow by up to 50% during allergy season to remove allergens from the air. Filter change indicator indicates when the carbon or True HEPA filter needs to be replaced.