This US neighborhood is full of hazardous air pollution. Can a network of sensors make ‘the invisible visible’?

Pacoima is hemmed in by highways and heavy industry, and its residents are fighting pollution with hyperlocal air quality monitoring Jose Luis Salas looks up at the ladder. “Are you ready?” he asks Shance Taylor, an environmental project manager who’s holding a white container, about the size of a shoebox, covered with wires and numbers. Taylor nods and climbs up to reach the side of Salas’s tidy house in Pacoima, a neighborhood in Los Angeles’s north-east San Fernando valley. The curious box...

By Katharine Gammon in Los Angeles with photographs by Thalia Juarez