BEFORE YOU BUY

■ Indoor air quality is under threat from wafted-in pollutants, allergens, dust particles, candles, open fires, volatile organic compounds (VOCS) from cleaning products and ‘offgassing’ – a process by which VOCS are released from paints and plastics for years. Using an air purifier is a great addition to any home and is especially beneficial if anyone in the family has asthma or allergies.

■ If you pick one room for your air purifier, choose the bedroom. You spend about a third of your life in there, usually with the door shut, and clean air will help promote sleep as well as being good for your health.

■ If you’re sensitive to noise, consider a model that’s quiet on its lowest setting, or one with an auto mode that is quiet unless it needs to work harder, which is unlikely overnight. A bedside timer is an option, but it’s better to have a quiet machine that you can leave on through the night.

■ To choose the right-sized machine, measure your floor space in square metres, then pick a machine that claims to clean the air in the room five times an hour. Ceiling heights are fairly consistent, so the measurement should be accurate enough.

■ HEPA filters catch dust, pollen, other allergens and even bacteria, so if you suffer from pet allergies or hay fever you’ll breathe cleaner air.

■ Air purifiers that use activated carbon filters will remove the

VOCS that cause odours, which could be a musty smell or the particulates from a scented candle or aerosol.

They are also great for filtering microscopic particles from traffic fumes, cigarette smoke and VOCS that carry smells – and can even remove viruses from the air.

air purifier needs around 10cm to ensure airflow in and out so can’t be placed too close to a wall or furniture

GINEVRA BENEDETTI, DEPUTY EDITOR