When you picture a city bus, an animal control van or a waste management truck, you’re probably not thinking about a high-tech, mobile urban sensing platform, about saving millions of lives, or about the smart city of the future. At least not yet. But a new initiative in Houston is turning public fleets into the rolling eyes and ears of the city, and enabling these vehicles to revolutionize the way air pollution is monitored, measured – and ultimately addressed across the United States.