Unless you live inside a smoke-belching chimney you probably think the air in your house is pretty clean. Apart from your guffs and the occasional slice of burned toast, what could possibly be making it dirty? The answer: invisible stuff. Things called Volatile Organic Compounds (VOCs) are released into the air by cosmetics, cleaning products and scented candles; fumes are created by cookers and fireplaces; and there are all kinds of allergens associated with plants and pets. Didn’t think about that lot, did you? Dyson has, though, gone and created the Pure Cool Me (£300) - an air-purifying fan that claims to filter out 99.95% of nasty particles floating about. You can either point it at your face or set it to rotate through 70 degrees, there’s a sleep timer onboard and Dyson’s boffins have made sure it’s as quiet as possible, so it won’t disturb your coughing and sneezing.