Better stoves can reduce indoor pollution
Air quality has improved dramatically in rich countries over the past century. Yet air pollution is still a huge problem, especially in the developing world. It kills about 7 million people each year, accounting for one out of every eight deaths globally. But the most deadly air pollution comes from inside people's houses, because 2.8 billion people still use firewood, dung and coal for cooking and keeping warm, breathing polluted air inside their homes every day.