 My name is Ron Prynne, and I'm a professor in the Department of Earth Atmospheric and Planetary Sciences at MIT. I asked Professor Prynne to join the show because he's an expert in the physics and chemistry of our climate system, and for decades has been leading a project to track the levels of refrigerants in the atmosphere. But before we get to what these gases are doing on our planet, let's talk about what they're doing in our homes.