Nearly half the world's population cooks on open fires, which kill nearly two million people every year due to wood-smoke-related diseases. Designed by Jonathan Cedar and Alec Drummond, the BioLite HomeStove reduces smoke emissions by more than 95% while serving as an affordable source of electricity to charge devices with USB ports such as mobile phones and LED lights. After field trials on four continents, BioLite is currently working with Columbia University's Mailman School of Public Health on a large health study to determine how advanced cook stoves can improve the health of pregnant women and infants. Two thousand stoves will be shipped to Ghana later this summer to begin the study; pilot programs are also planned for India and Kenya.