Dyson - FEATURES: Automatically captures gases and 99.95% of fine particles such as allergens and pollutants. Captures gases, odours and domestic fumes. Purifies all year-round. Cools you in summer. Automatically monitors, reacts and purifies then reports to your Dyson Link app.^ Night-time auto mode. * Particle capture tested to EN1822. Gaseous capture tested to JEM 1467 (acetic acid, acetaldehyde, ammonia) and GB/T18801 (formaldehyde, benzene). Gaseous capture rates vary. ^ App functionality may vary by location. Requires WiFi and an app enabled device. Standard data and messaging rates may apply.