Exposure to air pollution results in an estimated 7 million deaths each year, said the World Health Organization (WHO), double its previous estimate. This suggests that air pollution—indoor, outdoor, or both—caused 1 in 8 deaths worldwide in 2012.
The new estimate is based on more accurate pollution measurements in both urban and rural regions, made possible by newer technologies, and newer evidence linking pollution exposure to poor health. Although pollution has long been recognized as a risk factor in respiratory illnesses such as acute infections and chronic obstructive pulmonary disease (COPD), newer evidence suggests it also contributes to heart disease, stroke, and cancer.
Kuehn BM. WHO: More Than 7 Million Air Pollution Deaths Each Year. JAMA. 2014;311(15):1486. doi:10.1001/jama.2014.4031