What if fog isn't just misty air, but a living ecosystem? This question hung over cloud researcher Thi Thuong Thuong Cao. As a Ph.D. student at Arizona State University, her curiosity led her from knocking on the doors of microbiologists and chemists, to sampling fog before sunrise in Pennsylvania, to hours of peering through a lab's microscope. Finally, she found her answer. Her ASU research team found that bacteria floating in tiny fog droplets are alive, growing and (quite helpfully) breaking down pollutants in the air. ...read more read less