What is the key concept for this section? Describe the human body’s defenses against air pollution, how they can be overwhelmed, and the illnesses that can result. Approximately how many people die...

What is the key concept for this section? Describe the human body’s defenses against air pollution, how they can be overwhelmed, and the illnesses that can result. Approximately how many people die prematurely from outdoor and indoor air pollution each year in the world and in the United States? What percentage of these deaths are caused by indoor air pollution?