The fog is alive: Droplets host bacteria that clear toxins from our air

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.