Four stage purification system captures 9997 of airborne particles as small as 03 microns including pollen and other allergens dust mites mould spores pet dander and cigarette smoke aerasafetrade antimicrobial treatment ndash built in protection from the growth of odour causing bacteria mildew and fungi on true hepa filter aerasmarttrade sensor monitors the air quality and automatically adjusts the fan speed to keep your air purified blue amber and red lights indicate the purity