On this week’s show: Studying pollution from cannabis farms in the United States is difficult because of federal restrictions, and how processed foods complicate signaling from the gut to the brain [1:15] The “dank” smelling terpenes emitted by growing marijuana can combine with chemicals in car emissions to form ozone, a health-damaging compound. This is especially problematic in Denver, where ozone levels are dangerously high and pot farms have sprung up along two highways in the city. Host Sarah Crespi talks with reporter Jason Plautz about researchers’ efforts to measure terpene emissions from pot plants and how federal restrictions have hampered them. Read the news story: https://www.sciencemag.org/news/2019/01/legal-pot-farms-expand-so-do-air-pollution-worries [10:35] Next, host Meagan Cantwell talks with Dana Small, a professor of psychiatry and psychology at Yale University, about how processed foods are perceived by the body. In a doughnut-rich world, what’s a body to think about calories, nutrition, and satiety? Read the article ($): http://science.sciencemag.org/lookup/doi/10.1126/science.aav0556 [19:49] And in the first book segment of the year, books editor Valerie Thompson is joined by Erika Malim, a history professor at Princeton University, to talk about her book Creatures of Cain: The Hunt for Human Nature in Cold War America, which follows the rise and fall of the “killer ape hypothesis”—the idea that our capacity for killing each other is what makes us human. Visit the books blog: https://blogs.sciencemag.org/books/ This week’s episode was edited by Podigy https://podigy.co/ Listen to previous podcasts http://www.sciencemag.org/podcasts About the Science Podcast http://www.sciencemag.org/about/podcast [Image: Wornden LY/Flickr; Music: Jeffrey Cook]