This time, the 4th of July will see 'green fireworks' brighten the skies in an eco-friendly way in the US.
It is because researchers are developing new pyrotechnic formulas that replace environmental pollutant in the firecrackers with nitrogen-rich materials that burn cleaner and produce less smoke.
Fireworks, flares and other so-called "pyrotechnics" traditionally have included potassium perchlorate as the oxidizer, a material that provides the oxygen that fireworks need to burn.
Perchlorate, however, is an environmental pollutant with potential adverse effects on people and wildlife. Pyrotechnics contain other ingredients, such color-producing heavy metals, with a similar potential.
Studies have shown that perchlorate from community fireworks displays conducted over lakes, for instance, can lead to perchlorate contamination of the water.
Researchers, however, have developed new pyrotechnic formulas that replace perchlorate with nitrogen-rich materials or nitrocellulose that burn cleaner and produce less smoke, according to an article in ACS's weekly newsmagazine, Chemical and Engineering News (C and EN).
In the article, C and EN Associate Editor Bethany Halford says that these nitrogen-rich formulas also use fewer color-producing chemicals, dramatically cutting down on the amount of heavy metals used and lowering their potentially toxic effects.
Some of these fireworks have already been used at circuses, rock concerts and other events, but none have been used at large outdoor displays.
According to the article, the big challenge in launching these "eco-friendly" pyrotechnics into the sky is making them cost-competitive with conventional fireworks while maintaining their dazzle and glow.