Award-winning documentary photographer and multimedia journalist Larry C. Price traveled the world to report on air pollution around the world: specifically, PM2.5. These are particles are so small, they can pass through our lungs and into our bloodstreams, where they wreak havoc on our bodies. They're blamed for an estimated four million deaths per year, and they're the result of many human-driven and environmental factors. In this video, Price discusses the reporting that took him 50,000 miles on eight different trips around the world.