By far the most important factor is fine particulate matter pollution in urban air.[7] Similarly, environmental exposures have been estimated to contribute to 4.9 million (8.7%) deaths and 86 million (5.7%) DALYs globally.[8] In the United States, Superfund sites created by various companies have been found to be hazardous to human and environmental health in nearby communities. It was this perceived threat, raising the specter of miscarriages, mutations, birth defects, and cancers that most frightened the public.[9]