Global urbanization has led to one of the world’s most pressing environmental health concerns: the increasing number of people contributing to and being affected by air pollution, leading to 7 million early deaths each year. The key issue is human exposure to pollution within cities and the consequential effects on human health.

With new research conducted at MIT’s Senseable City Lab, human exposure to air pollution can now be accurately quantified at an unprecedented scale. Researchers mapped the movements of several million people using ubiquitous cell phone data, and intersected this information with neighborhood air pollution measures. Covering the expanse of New York City and its 8.5 million inhabitants, the study reveals where and when New Yorkers are most at risk of exposure to air pollution - with major implications for environment and public health policy.