For people living in areas struggling with air pollution, UC Berkeley students have created a keychain-sized device that would monitor air quality, providing consumers with quantitative data to assess their local environments.

The wearable device, called Clarity, was developed by undergraduates David Lu, Deepak Talwar and Hannah Hagen, who co-founded a company in February to create the device. The students are now working on the device’s second prototype, which is set to be tested early next year.

Clarity measures particulate matter in the air as well as temperature and humidity. Sensors inside reflect light off matter entering the device, measuring the size and number of particles before syncing the information, via bluetooth, with the Clarity app.

The app, also under development, would record data and warn users when they’re entering a polluted area.

This technology could prove especially relevant to Clarity’s primary target market, China, which has the world’s worst air pollution and biggest consumer market, according to Lu, an international student from China who is currently taking a gap year after his sophomore year.

“In China, air pollution is worse than it was in America 30 years ago,” said Lu, who is double majoring in environmental engineering and atmospheric science. “We see these devices as a tool for the community to make them aware of the environment they’re living in so that we can start a movement.”

The team began development last semester at the Foundry@CITRIS — a technology incubator based in UC Berkeley’s Sutardja Dai Hall — which selects projects and provides them with working space, laboratory resources and $10,000 in seed funding to build companies, Lu said.

From there, with an additional team of software and hardware engineers, the team spent most of this summer in Shenzhen, working with a startup accelerator called HAXLR8R that provided another round of seed funding, according to Lu.

Clarity’s air-quality sensor will enter a highly competitive and promising market, according to Ron Cohen, director of the campus Berkeley Atmospheric Science Center, who has conducted research with sensors that detect carbon.

Developers of these kinds of sensors often face difficulties packaging the sensor so that it still measures accurately and mass producing a product that functions just as well as the prototype, Cohen said.

Despite these challenges, Cohen remains optimistic for applications of small sensors, which he said could be used to provide accurate information on air pollution that will help inform the debate on climate change.

“In the long run, small sensors are going to change a lot of things about how we think about the world,” Cohen said. “I’m extremely excited — cautious but excited.”

Lu said he hopes to have the app and device on the market in May or June of 2015.