By Ryan Johnson Air pollution kills. In the United States, 1 of every 25 deaths occurs prematurely because of exposure to outdoor air pollution. It kills more Americans than all transportation accidents and gun shootings combined. More than diabetes or than breast cancer plus prostate cancer. More than Parkinson’s disease plus leukemia plus HIV/AIDS. And […]

Thirty years after nations banded together to phase out chemicals that destroy stratospheric ozone, the gaping hole in Earth’s ultraviolet (UV) radiation shield above Antarctica is shrinking. But new findings suggest that at midlatitudes, where most people live, the ozone layer in the lower stratosphere is growing more tenuous—for reasons that scientists are struggling to […]