Spike in pollution due to July 4 fireworks.

• Position: Independence Day

The Fourth of July has been synonymous with fireworks. While many grew up learning that these explosives can be dangerous to the eyes and hands if not handled properly, they also produce air pollutants, including particulate matter, that can affect health.

Dian Seidel and Abigail Birnbaum of the National Oceanic and Atmospheric Administration have authored a study that quantifies the surge in fine particulate matter-particles that are two-and-one-half microns in diameter (PM2.5)--on July 4, using observations from the 315 U.S. air quality monitoring sites that operated from 1999 to 2013. While scientists have known that fireworks displays produce a surge in fine particulates, this study is the first nationwide quantitative analysis of the effects.

"We chose the holiday not to put a damper on celebrations of America's independence, but because it is the best way to do a nationwide study of the effects of fireworks on air quality," says Seidel, a senior scientist at NOAA's Air Resources Laboratory, College Park, Md. "These results will help improve air quality predictions, which currently don't account for...