In the U.S., 1 out of 10 children suffers from asthma. It is the number-one illness that causes kids to miss school. Each year, coal pollution causes 12,000 emergency room visits and $100 billion in health costs. Half of U.S. families live in places with unsafe air. Pollution from coal-fired power plants creates smog, which can cause chest pain, coughing, and breathing difficulties. Smog can make conditions like bronchitis, emphysema, and asthma worse or even fatal.