Lillian Njuu, pictured here, says she’s willing to pay for a clean cookstove because of the health benefits for her family

Do you know the leading cause of death in children worldwide? It kills an estimated 1.4 million children under 5 each year—more than malaria, tuberculosis and AIDS combined. Many will be surprised to learn that the answer is pneumonia, an acute lung infection that can be treated with antibiotics and prevented with immunization, adequate nutrition and simple environmental interventions.