Fourth of July fireworks can bring a toxic brew of air pollution to our atmosphere, according to federal scientists.
Exploding fireworks unleash tiny particles (about 1/30th the diameter of a human hair) that can travel deep into a person's respiratory tract and enter the lungs.
Known as "particulate matter," the particles include dust, dirt, soot, smoke and liquid droplets. They are measured by micrometers, according to the National Oceanic and Atmospheric Administration (NOAA).
The particles are linked to a range of health effects, from coughing and shortness of breath to heart attack and stroke, says a report published in the journal Atmospheric Environment.
The air is at its worst between 9 p.m. and 10 p.m. during the holiday. Levels drop by noon on July 5.
"The study is also another wake-up call for those who may be particularly sensitive to the effects of fine particulate matter," says NOAA scientist Dian Seidel, the study's lead author.
