U.S. Air Quality Slips After Decades of Improvement
Jun 19, 2019, 10:18 AM
After decades of improvement, America's air may not be getting any cleaner.
Over the last two years the nation had more polluted air days than just a few years earlier, federal data shows. While it remains unclear whether this is the beginning of a trend, health experts say it's troubling to see air quality progress stagnate.