Recent studies have revealed how chemists are using rare-earth alloys to create sparklers and pyrotechnics with rare green coloring. But where do they stand on “greenness” when it comes to environmental impact?
In a recent article on Axial, we explored how researchers are customizing fireworks with binary metal alloys, including yterrbium, which can produce a deep green color—previously unknown in commercial pyrotechnics, whose spark colors have traditionally been limited to dark red, gold, or white.1 But what about the other kind of green?
Pretty Lights, Damaging Impact
Fireworks are usually made up of oxidants, fuel, coloring agents, binders, propellants, and sound or smoke agents.2 Even short-term peaks in ambient particulate matter (PM) concentrations are known to have negative impacts on respiratory and cardiovascular health, and the evidence suggests that organized firework displays frequently exceed local PM thresholds. Large fireworks events also increase atmospheric levels of trace metals and pollutants such as NO and SO2.3
Research in London during two annual festivities, Guy Fawkes Night and Diwali, revealed that the contribution of celebratory fireworks to the total oxidative potential of PM was greater than that of traffic emissions.3 This oxidative potential refers to the capacity of PM to drive the oxidation of physiologically vital lung antioxidants, which could be related to acute respiratory outcomes.
This is not an inconsequential contribution, with fireworks and related explosives accounting for more than 250 tons of copper, strontium, barium, magnesium, and potassium in the UK alone—representing 6% and 8% of annual atmospheric releases of copper and magnesium, respectively.4
Due to this severe short-term air pollution, there have been efforts to develop environmentally friendly fireworks with reduced emissions of around 50% compared to traditional products.5 Some of these innovations include clean-burning, smokeless fireworks, those with a sulfur-free propellant charge, and strontium- and chlorine-free formulations.6-8
Other groups have focused on finding replacements for traditional oxidizers such as potassium- or ammonium perchlorate, which are highly soluble in water and may be detrimental to groundwater quality. One recent study in ACS Applied Materials & Interfaces reveals the potential of several alkali/alkaline earth metal salts as promising alternatives for more sustainable, cost-effective pyrotechnic formulations.9
Another possible solution for greener fireworks is energetic coordination polymers (ECPs), which are composed of strong coordination bonds between energetic ligands and metal ions, giving them both high density and thermal stability.2 When ECPs include alkaline and earth alkaline metals, they can produce beautiful and diverse colors during combustion while reducing the use of oxidants such as chlorine, sulfur, and heavy metals.2,9,10 Ceric ammonium nitrate stabilized by treatment with stearic acid has also been proposed as a replacement for ammonium perchlorate in pyrotechnic strobe formulations.11
Despite these advances, the jury still seems to be out on fireworks with a lower ecological impact, with most governments prepared to accept the inevitable pollution for one-off events. For the time being, innovative greener products also cost significantly more than the traditional mass-produced offerings. But as research progresses and consumers press for better environmental alternatives, we should see new options skyrocket.
Explore More Research from ACS Journals
Effect of Biomass Burning, Diwali Fireworks, and Polluted Fog Events on the Oxidative Potential of Fine Ambient Particulate Matter in Delhi, India
Significant Reduction in Fine Particulate Matter in Beijing during 2022 Beijing Winter Olympics
New Green Bio-Based Binder to Reduce the Poisonous and Harmful Gases Generated from the Combustion of Pyrotechnics
Top Development of Green-Light Pyrotechnics: Hypergolic Cu(II)-Based Coordination Polymers
- Memmel, P. et al. Customizing the Appearance of Sparks with Binary Metal Alloys. ACS Omega 2022, 7, 32, 28408–28420
- Dong, W.-S.et al. Multidimensional Energetic Coordination Polymers as Flame Colorants: Intriguing Architecture and Excellent Performance. Cryst. Growth Des. 2022, 22, 9, 5449–5458.
- Godri, K.J. et al. Particulate Oxidative Burden Associated with Firework Activity. Environ. Sci. Technol. 2010, 44, 21, 8295–8301.
- Passant, N. Emission factors programme task 1: summary of simple desk studies. DEFRA: London, United Kingdom, 2003.
- Fan, S. et al. Are Environmentally Friendly Fireworks Really “Green” for Air Quality? A Study from the 2019 National Day Fireworks Display in Shenzhen. Environ. Sci. Technol. 2021, 55, 6, 3520–3529.
- Yu, J. Y. et al. Thermal hazard research of smokeless fireworks. J. Therm. Ana. Calorim. 2012, 109, 1151–1156.
- Sun, Y. et al. Preparation and performance of environmental friendly Sulphur-Free propellant for fireworks. Appl. Therm. Eng. 2017, 126, 987–996.
- Glück, J. et al. A Strontium- and Chlorine-Free Pyrotechnic Illuminant of High Color Purity. Angew Chem. Int. Ed. 2017, 56, 16507–16509.
- Cao, W. et al. Access to Green Pyrotechnic Compositions via Constructing Coordination Polymers: A New Approach to the Application of 3,4-Dinitropyrazole. ACS Appl. Mater. Interfaces 2022, 14, 28, 32084–32095.
- Yang, J. et al. Alkaline and Earth Alkaline Energetic Materials Based on a Versatile and Multifunctional 1-Aminotetrazol-5-one Ligand. Inorg. Chem. 2018, 57, 24, 15105–15111.
- Dettlaff, H. et al. Microscopic Studies and Application of a Stabilized Ceric Ammonium Nitrate Oxidizer in Environmentally Friendly Pyrotechnic Strobes. Inorg. Chem. 2022, 61, 26, 9930–9934.