The Earth’s environment faces some great challenges, and it doesn’t take much to realize there’s no time to waste. In our third episode, we meet scientists who believe that nanotechnology may be the key to overcoming the biosphere’s environmental problems. Dr. Vicki Colvin from Rice University field tests a simple low-cost technique that could help the developing world clean arsenic out of contaminated groundwater.The University of Toronto’s Professor Ted Sargent outlines his research into nano solar cells that would make solar power cheaper and more efficient by capturing the sun’s infrared rays. Professor Peter Dobson from Oxford University describes how adding cerium oxide in nano form to diesel fuel can make it both more efficient and clean up emissions. At the University of Western Ontario Dr. Dennis O’Carroll demonstrates nano remediation of contaminated soil.But are we creating pollutants that are more dangerous than the ones we already have? What happens when nano-structured materials decay? The episode also visit Duke University in North Carolina, where Professor Mark Wiesner’s team is investigating the possible environmental impact of silver nanoparticles already being used in anti-bacterial consumer products. So, will nanotechnology save the Earth’s environment? Or will it provide another way in which humans can harm nature?