They can be found on raincoats, non-stick pans and plastic packaging. In the last 50 years, PFAS – short for per- and polyfluoroalkyl substances – have made their way into many of our everyday objects. Dubbed "forever chemicals", they're extremely persistent and can stay in the air, water and soil for decades, harming the environment and ultimately our health. Is PFAS pollution irreversible? And what can we do to protect ourselves? We take a closer look in the edition of Down to Earth.