A major study published in the online medical journal: "JAMA Open Network" has confirmed that an increased risk of premature births and low birth weights is significantly associated with exposure to air pollution and excessive heat during pregnancy. Low income communities and Black women specifically were among the most vulnerable group. The peer-reviewed study was based on a review of more than 32 million U.S. births. Chris and Nell of This Green Earth speak withJuanita Constible, a health policy expert in the Climate and Clean Energy program at the Natural Resources Defense Council about this paper.