Reversing Downward Trend, US Air Pollution Creeps Back Up

PM2.5 particles can be breathed in by humans and travel through the respiratory tract into the lungs. (Photo: Pxhere)

Fine particulate matter has been on the rise in the U.S. since 2016, a disturbing reversal in recent U.S. air pollution trends for environmentalists.

A new study released this October by the National Bureau of Economic Research (N.B.E.R.) found that fine particle air…