ULTRA QUIET: Quieter than a whisper at only 18 dB on low fan speed, Quiet Mark certified air purifier, perfect for use in your bedroom for a good night sleep. INDEPENDENTLY TESTED FOR PERFORMANCE & SAFETY, ZERO OZONE: AHAM Verifide for Performance (CADR); Quiet Mark Certified; Ozone Safety Standards Certified by CARB; Zero Ozone Verified (<5 ppb) by Intertek Sustainability.