A third of the world's population cooks with fuels that produce harmful fumes when burned. Breathing in the fine particles produced by cooking with wood, charcoal, coal, animal dung and agricultural waste can penetrate the lungs and cause multiple respiratory and cardiovascular problems, including cancer and strokes. Women and children are most at risk. Fifty countries gathered in Paris on Tuesday to raise funds to replace dangerous cooking with clean ones. Marco Werman speaks with Dymphna van der Lans, CEO of the Clean Cooking Alliance.