Fireworks may dazzle crowds with brilliant colors and loud explosions, but new research suggests their effects continue long after the show ends. Three recent studies published in American Chemical Society (ACS) journals examined what fireworks leave behind, from discarded debris and airborne particles to chemical compounds released into the atmosphere.
Together, the findings offer a clearer picture of how fireworks can influence air quality, water chemistry, and potentially both human health and the environment.
Firecracker Debris Can Alter Water Chemistry
Once fireworks burn out, they leave behind more than ash. Spent firecrackers scatter residue that contains partially burned fuel, metal salts, additives, and pieces of charred packaging.
In a laboratory study published in Environmental Science & Technology, researchers found that this debris released significant amounts of metal ions (e.g., potassium and manganese) and dissolved organic matter (e.g., simple phenols and sulfur-containing compounds) when placed in lake and river water. At the same time, the leftover solid material absorbed some dissolved substances that were already present in the water, including larger, more complex compounds.
According to the researchers, these chemical changes could interfere with microbial communities and aquatic ecosystems, particularly if large amounts of firecracker litter are repeatedly washed into rivers and lakes after festivals or celebrations. Properly collecting and disposing of spent fireworks could help reduce these environmental effects.
Fireworks Add to Air Pollution During Large Events
Fireworks are only one source of pollution at major public celebrations, but researchers wanted to understand how much they contribute compared with other activities.
In a study published in ACS ES&T Air, scientists monitored particulate matter during a large, multi-day athletic event in the United Kingdom. They detected sharp, short-lived increases in both coarse and fine airborne particles throughout the event.
The team linked much of the pollution to cooking emissions from food vendors and dust stirred up by vehicles. During the opening and closing ceremonies, however, they observed two distinct spikes in fine particulate matter. The first occurred as crowds arrived and dust levels increased, while the second, slightly smaller spike coincided with the fireworks displays.
The researchers estimated that people who attended every day of the event were exposed to air pollution levels exceeding the World Health Organization’s recommended limits, suggesting that large celebrations can significantly increase exposure to fine particulate matter.
Fireworks Release More Than Smoke Into the Air
Another study focused on chemicals called amines, which are included in some firework formulations. These compounds can react in the atmosphere to form aerosols that contribute to haze and reduced air quality.
To determine what happens to these chemicals during fireworks displays, researchers measured amines in both gases and airborne particles during Lunar New Year celebrations in a suburban area of China.
The findings, published in Environmental Science & Technology Letters, revealed substantial increases in several amines compared with a non-celebratory period. The biggest increases occurred during the largest fireworks displays. Scientists also recorded higher levels of other firework-related pollutants, including fine particulate matter and sulfate and potassium ions.
The researchers say the results suggest that fireworks contribute more than visible smoke to the haze that often lingers after major celebrations, adding another layer to their environmental impact.
