Particulate air pollution is a serious human health hazard in locations around the world, connected to nearly seven million deaths each year. Recently, the digital science magazine Undark (featured in the 2017 Best of the Scout Report) published Breathtaking, a special series of articles focused on a specific classification of particulate pollution, PM2.5. Here, readers are taken on a journey that "visit[s] seven countries on five continents, rich and poor, north and south, to examine the impacts of this sort of air pollution on the lives of everyday people" and also looks at whether and how this deadly problem is being addressed. Locations include California's San Joaquin Valley, where one in six children are estimated to have asthma due to the region's recurring air pollution, and Macedonia, whose coal-based electricity and political difficulties contribute to its "reputation for having some of the worst annual average air pollution in Europe." Accompanied by many highly visual photographs, videos, and interactive graphics, Breathtaking provides an informative and engaging exploration of worldwide particulate pollution. This series was produced jointly by Undark and the Pulitzer Center on Crisis Reporting.