Wynd
Wynd aims to help people stay aware of the air around them, and provides the means to clean it up. They have built several patented technologies: a wearable air quality monitor, a powerful personal air purifier, and a comprehensive mobile app that displays deep insights about your environment. They have users all over the world, and their goal is to create a crowdsourced, ultra-granular air quality map of the entire globe. They aim to make the invisible visible.