Dust is everywhere: under our beds, on our computer screens, in cracks in the sidewalk, and on our skin. Particles from the Sahara can be found as far away as the Caribbean, and dust from melting glaciers can impact the Earth’s climate. On this week’s edition of Please Explain, Hannah Holmes, author of The Secret Life of Dust, and Paul Lioy, Professor and Deputy Director of Environmental and Occupational Health Sciences at Robert Wood Johnson Medical School-University of Medicine and Dentistry of New Jersey, and author of the forthcoming book Dust: The Inside Story of Its Role in the September 11th Aftermath, join us to discuss where dust comes from, what it’s made of, and the good and bad contributions it makes to the planet and even to space.