NEW YORK — July Fourth fireworks fill the skies across the nation with more than sparkling bursts of color. They spew pollution, too.
A study of 315 locations around the country found that the holiday explosions temporarily boosted the levels of airborne microscopic particles that can pose a health risk.
At 9 p.m. and 10 p.m. on July 4, levels of those particles were more than twice normal, on average, researchers found. But they tapered off overnight and fell back to normal by noon on July 5.