An Air-Quality Monitor You Take with You

MIT Technology Review: “A startup is building a wearable air-quality monitor using a sensing technology that can cheaply detect the presence of chemicals around you in real time. By reporting the information its sensors gather to an app on your smartphone, the technology could help people with respiratory conditions and those who live in highly polluted areas keep tabs on exposure.
Berkeley, California-based Chemisense also plans to crowdsource data from users to show places around town where certain compounds are identified.
Initially, the company plans to sell a $150 wristband geared toward kids with asthma—of which there are nearly 7 million in the U.S., according to data from the Centers for Disease Control and Prevention— to help them identify places and pollutants that tend to provoke attacks,  and track their exposure to air pollution over time. The company hopes people with other respiratory conditions, and those who are just concerned about air pollution, will be interested, too.
In the U.S., air quality is monitored at thousands of stations across the country; maps and forecasts can be viewed online. But these monitors offer accurate readings only in their location.
Chemisense has not yet made its initial product, but it expects it will be a wristband using polymers treated with charged nanoparticles of carbon such that the polymers swell in the presence of certain chemical vapors, changing the resistance of a circuit.”