If you happen to live in a big city, air pollution is no doubt a grim ever-presence in your mind. Those in our own great capital need only look at its nickname for a reminder. But short of hiding under a duvet indoors for the rest of your life (tempting, but ultimately not a great idea) what can you do to battle the smog? Plume Labs says you should buy its brand new smart air quality tracker, Flow. Paired with the AI-enabled companion app, it can track the full range of indoor and outdoor pollutants, offer personalised advice on how to steer clear of risk areas, and share the data you collect over time with other users. Preorder for USD$139.