PHILIPS SERIES 2000i SMART AIR PURIFIER

£339.99, amazon.co.uk

THIS has both HEPA and activated carbon filters, and in a study carried out in a 300sqft room – the size of an average open-plan living room and kitchen – it removed up to 99.9 per cent of flu virus from the air.

It can change the air in a 215sqft space – similar to a large bedroom – nearly six times an hour.

It uses 56 watts of energy per hour on its maximum setting – equivalent to a standard lightbulb.

In the deodorant test, the device reacted immediately, flashing red for poor air quality, and took 19 minutes to return the air to ‘good’.

The activated carbon filter costs £25 and needs replacing every 12 months, based on 16 hours a day use. The HEPA filter costs £34.99 and needs replacing every two years. A warning light indicates when the filters need to be replaced.