Particulate or particle air pollution is made up of microscopic pieces of dust, dirt, smoke and soot mixed with liquid droplets. The finest particles regulated by the EPA are 2.5 micrometers; to put that in perspective, a strand of human hair is 70 micrometers, or more than 30 times larger.
Anything less than 10 micrometers can not only enter the lungs, it can pass into the bloodstream, where it is carried to various organs and begins a chronic inflammatory reaction thought to lead to disease.
"Ten or 15 years ago, we thought that air pollution caused pneumonia, asthma and bronchitis and not much more than that," said Dr. Philip Landrigan, dean for global health at Icahn School of Medicine at Mount Sinai in New York, who was not involved in the study. "We now know that air pollution is a very important cause of heart disease and stroke and contributes to chronic lung disease, lung cancer and chronic kidney disease."
Over 30 million Americans have diabetes, and the numbers worldwide are staggering: According to WHO, 422 million adults had been diagnosed by 2014, compared with 108 million in 1980. Low- and middle-income countries least able to manage the disease were experiencing the most growth.