Study: Fireworks cause a toxic brew of unhealthy air

The thousands of Fourth of July fireworks celebrations across the nation bring a toxic brew of air pollution to our atmosphere, according to a recent study from federal scientists.

The exploding fireworks unleash tiny particles — about 1/30th the diameter of a typical human hair — that can affect health because they travel deep into a person's respiratory tract, entering the lungs.

The tiny particles are known as "particulate matter" and include dust, dirt, soot, smoke and liquid droplets and are measured in micrometers, according to the Environmental Protection Agency. A micrometer is one-millionth of a meter.

The fine particulate matter in this study — which was led by scientists from the National Oceanic and Atmospheric Administration — were 2.5 micrometers in size.

Both long- and short-term exposures to fine particles are linked to a range of health effects — from coughing, wheezing and shortness of breath, to asthma attacks, heart attack and stroke, to even premature death in people with heart or lung disease, according to the study.

On average, the air is at its worst from 9 p.m. to 10 p.m. on the holiday, the study found. But levels drop back down by noon on July 5.

"These results will help improve air quality predictions, which currently don't account for fireworks as a source of air pollution," said NOAA scientist Dian Seidel and study lead author.

"The study is also another wake-up call for those who may be particularly sensitive to the effects of fine particulate matter," she said.

The study appeared in the journal Atmospheric Environment.