How do you ensure action on air pollution doesn’t lead to unanticipated consequences? From London to Guangzhou, Nepal to Rwanda, air pollution is rising up the political agenda as evidence of its far-reaching health consequences increases. Data on air pollution is improving but the data is worrying; population-dense locations around the globe have unsafe levels of particulates. While better data is critical, alone it is not enough to make for change. Understanding the real-world impacts of vaunted pollution solutions is key.