Cities where US embassies installed air monitors saw improved air quality. //

In 2008, the United States embassy in Beijing installed an air-quality monitor and started tweeting out its findings every hour. Since then, these monitors have popped up in more than 50 embassies in countries and cities around the globe.

Something unexpected happened in each of the cities in which the monitors appeared. Researchers found that, overall, air quality improved in the cities where embassies were tweeting out air-quality data. “We were surprised,” Akshaya Jha, assistant professor of economics and public policy at Carnegie Mellon University and one of the paper’s authors, told Ars.