An estimated 3 billion people in the world still cook with open fires and dirty cookstoves, including this mother in Guatemala. Credit: Photo by Nigel Bruce, University of Liverpool Two new studies led by University of California, Berkeley, researchers spotlight the human health effects of exposure to smoke from open fires and dirty cookstoves, the primary source of cooking and heating for 43 percent, or some 3 billion members, of the world's population. Women and young children in poverty are particularly vulnerable. In the first study, the researchers found a dramatic one-third reduction in severe pneumonia diagnoses among children in...