Air pollution is a major environmental risk to health. Globally, the World Health Organization estimates that 3.7 million people per year die from the effects of air pollution, both urban and rural (WHO, 2014). Approximately 80% of air pollution-related deaths were due to coronary artery disease, while 14% were due to chronic obstructive pulmonary disease (COPD) or acute lower respiratory tract infections. The majority (~87%) of these premature deaths occurred in low- and middle-income countries (WHO, 2014). Although air quality in the U.S. has generally improved substantially in recent decades, air pollution remains a significant cause of poor health. Learn more about some of the health concerns related to air pollution below.