Air purifiers are great to have for most people—and essential if you suffer from allergies. The Zigma Aerio-300 smart air purifier has all the air cleaning features you could want, but it also connects to the internet, so you can control it with your smartphone, Google Home, Alexa, and so on. On top of that, it features a built-in PM2.5 sensor so you can see exactly how clean (or not) your indoor air is, and compare it to the outside world.