- Douglas Brugge and Kevin James Lane
- Read Time: 6 mins
Fine particulate matter smaller than 2.5 millionths of a meter, known as PM2.5, was the fifth-leading cause of death in the world in 2015, factoring in approximately 4.1 million global deaths annually. In the United States, PM2.5 contributed to about 88,000 deaths in 2015 – more than diabetes, influenza, kidney disease or suicide.