The HealthProtect 7410i is a sizeable unit, measuring more than two feet tall and weighing nearly 28 pounds. Its upright design makes it a bit awkward to move around, but two wheels on the back of the unit let you drag it like a vacuum cleaner, albeit this is a bit awkward. Smart features aside, one of the unit's biggest selling points is its ventilation design. While the typical high-end air purifier draws dirty air in through the bottom and ejects filtered air through the top, the HealthProtect pulls air in from the sides of the device, passes it through a unique V-shaped pair of filters, then ejects it via outlets positioned all around the device. Blueair's V-shaped filter pair has an embedded RFID chip that tracks its use and sends a message to the app when it's time for a replacement.

Living in a dense urban environment brings many startup-fuelled conveniences, be it near instant delivery of food -- or pretty much whatever else you fancy -- to a whole range of wheels that can be hopped on (or into) to whisk you around at the tap of an app. But the biggest problem afflicting city dwellers is not some minor inconvenience. And there's no app to fix that. Nor can hardware solve this problem. But smart hardware can at least help. For about a month I've been road-testing a wi-fi connected air purifier made by Swedish company, Blueair. It uses an Hepa filtration system combined with integrated air quality sensors to provide real-time in-app feedback which can be reassuring or alert you to unseen problems. If you're even vaguely environmentally aware it's fascinating and not a little horrifying to see how variable the air quality is inside your home. Everyday stuff like cooking, cleaning and changing the sheets can cause drastic swings in PM 2.5 and tVOC levels.