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Which air purifier should you buy?

Breathe easy

As cities choke on polluted air, purification technology is developing rapidly. Natasha Loder takes in a lungful

As cities choke on polluted air, purification technology is developing rapidly. Natasha Loder takes in a lungful

Natasha Loder | February/March 2018

Like most pregnant women, Sophie Power was devoted to the health of her unborn child. “I was eating my fruit and vegetables, I was doing everything, and then I came across a study on air pollution,” she says. What she discovered horrified her. She realised that her daily walk down Euston Road, one of London’s main arteries, had exposed her son to pollution that could shrink his lungs by 5-10%. She recalls thinking, “I have to do something about this.” So she founded AirLabs, a startup dedicated to improving human health by creating clean-air zones in cities.

Scientists have devised a number of ways to remove pollutants from air. Foam and fibreglass filters can strip out small particles. Absorbent materials like activated charcoal can trap odours, fumes and chemicals such as sulphur dioxide on their surface. But no consumer technology has so far proved capable of removing much nitrogen dioxide, which is known to cause a range of respiratory problems. AirLabs believes that it has found a solution by combining traditional methods with a new proprietary filter that uses carbon nano-particles. Scrubbed air from units inside products, such as garden furniture, create clean-air zones outside – useful if you want to eat al fresco near a busy street. Cars, too, are prone to accumulating high levels of contaminants while drivers are idling in traffic, so the firm has developed Airbubbl, a unit that will work inside the cabin, removing 95% of the pollutants. It will go on sale in May.

AirLabs is also exploring ways of integrating its technology into everyday items such as scarves or masks. There is a pressing need to deal with the threat of air pollution. Many large cities across the world are suffocating in smog. Particles with a diameter of less than two-and-half microns – about one-thirtieth of the width of a human hair – are known as PM 2.5s. They are capable of burrowing deep into the respiratory tract. In November, schools in Delhi were closed thanks to concentrations of PM 2.5 particles that peaked at more than 30 times the maximum level advised by the World Health Organisation (WHO). Residents of cities such as London, Beijing and Madrid suffer seasonal problems. All told, air pollution around the world is causing an increased risk of an enormous number of maladies, from lung cancer, respiratory infection and stroke, to cardiovascular disease and chronic obstructive pulmonary disorder. Staying indoors can be worse because of harmful chemicals given off by cooking, candles and cleaning products.

The market for anti-pollution technology is growing fast. It is getting much cheaper to manufacture sensors at high volume and low cost. According to IDTechEx, a market-research firm, the market for gas sensors, worth $361m in 2017, will exceed $2.4bn by 2022. These will be embedded everywhere: in windows and mobile phones, in wristwatches and bracelets.

One nifty idea comes from Velux, the window-maker, which is developing automated roof windows, blinds and shutters in collaboration with Netatmo, a smart-home company. Air pollution sensors will monitor the air inside and outdoors; if the air outside is cleaner than indoors, the windows will open. Patent applications by Apple and Samsung show that these companies are interested in inserting air-quality sensors into mobile phones, a feature that will make the brands particularly attractive in China.

It is not just the wealthy who can benefit from this technology. The Grameen Trust, a not-for-profit organisation, has developed, in conjunction with Intel’s charitable arm, a cheap, smart bangle with an integrated carbon-monoxide detector. When it detects dangerous levels of this toxic gas, a red LED flashes and a recording warns the wearer to open the doors and get outside. This inexpensive jewellery could save countless lives, especially those of women in developing countries at risk from dangerous cooking fumes.

Unsightly, room-dominating air purifiers are being challenged by discreet, portable models. Wynd, a California based startup, has produced a purifier the size of a water bottle that weighs less than half a kilogram (more than 30 times lighter than Blueair’s Classic). Smaller purifiers have tended to struggle with processing large volumes of air. Wynd’s engineers solved this by designing a filter with 42 pleats, which keeps the purifier compact while maximising the amount of air passing through it. Coway’s Mighty, meanwhile, weighs only 6kg but can clean rooms up to 528 square feet in size, thanks to a four-stage filtration system that uses an ioniser alongside the standard HEPA filter. David Pugh, a technology analyst with IDTechEx, notes that air purifiers sold by Dyson and Philips also monitor air quality, so users can see whether the air they breathe is getting cleaner.

Increased awareness of the treacherous quality of much of our air may be terrifying but, in the long run, it will provoke demand not just for devices that clean the air but also for technologies such as electric vehicles and solar power that generate less pollution. Outrage at the smog that fills our lungs should thus allow future generations to breathe more easily.

They'll take your breath away
Wynd: $199. Coway Mighty: £180/$229. Blueair Classic 505 for the office: £627/$799.99. Dyson Pure Cool Link desk purifier: £349.99/$485. Philips AC2889/60 for medium to large rooms: £400/$399.99