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Do fireworks harm the environment?
The question is topical, as the International des Feux Loto-Québec begins on Thursday. Fireworks have aroused wonder for more than 1000 years, but the breathtaking spectacle they offer us sometimes makes us forget that they pollute the environment and affect human health.
Simply knowing the composition of these aerial bombs, as high-range fireworks are called, is enough to understand that their explosion is harmful both to the atmosphere and to the soil and water.
Fireworks mainly contain black powder — a mixture of sulfur, coal (carbon) and potassium nitrate (saltpeter) or perchlorate (oxidizers) — which, once ignited, propels the bomb and exploded. Added to this are various chemical elements which give particular colors to the flaming showers which unfold in the sky.
When they explode, these bombs release gases, fine particles, as well as various toxic compounds, such as perchlorates, oxides and metals, summarizes Gabrielle Lajoie in her master’s thesis, which she submitted to the University of Sherbrooke in 2018. In this document which relates a multitude of scientific studies, Mme Lajoie exposes all the impacts that fireworks can have on the environment.
Atmospheric pollution
The explosion of fireworks releases a large quantity of gas into the air, including a large proportion of carbon dioxide. This explosion also releases sulfur dioxide (SO₂) — a major air pollutant — and nitrogen oxides (NOₓ), which form during the decomposition of black powder and which are responsible for the acidification of precipitation (rain acids).
Subjected to solar radiation, nitrogen dioxide can also produce ozone in the troposphere, the lowest layer of the atmosphere, where this substance contributes to the greenhouse effect and is considered a pollutant that would cause ” premature aging of plants.
The clouds of smoke generated by bomb explosions are composed of fine particles that are made up mainly of carbon and metals, as well as “secondary compounds such as nitrates, sulfates, oxalates, malonates, succinates and glutamates.”
Pyrotechnic events are the cause of the worst air quality indices on the island of Montreal. They generate much higher levels of particulate matter than those observed during smog alerts.
While the coarsest particles fall quickly to the ground, the finest ones can remain in the atmosphere for several days and thus be transported over long distances. Those that remain suspended in the air can influence the diffusion and absorption of solar radiation, as well as cloud dynamics, thereby disrupting “the Earth’s hydrological cycle,” explains M.me Lajoie in his memoir.
The deposition of this particulate matter would alter the composition of the soil, which would disrupt the photosynthetic process of plants which draw their nutrients from it and, as a result, reduce their growth rate.
“Pyrotechnic events are the cause of the worst air quality indices on the island of Montreal. They generate much higher levels of particulate matter than those observed during smog alerts,” warns the researcher.
“Concentrations of fine particles equal to 10,000 micrograms per cubic meter [µg/m³] were measured during a performance of the International des Feux Loto-Québec, while the health threshold is 10 µg/m³,” she relates.
Water contamination
Fireworks are also blamed for “the increasing contamination of the environment by perchlorate (ClO4). Very soluble in water, where it remains stable and inert, perchlorate can persist for years, even decades in surface and groundwater,” says M.me Joy.
Rich in metals, fireworks release significant quantities into the environment, particularly in particulate matter.
A report from the United Kingdom’s Department for Environment, Food and Rural Affairs stated that “approximately 73 tonnes of magnesium (which gives the white color), 65 tonnes of barium (green color), 10 tonnes of strontium (red color), five tons of titanium (white color) and three tons of copper (blue color) were released into the environment following pyrotechnic activities in 2002.”
Added to this are other less commonly reported metals, such as cobalt, vanadium, nickel, mercury, bismuth, gallium and antimony, which are also seeing their concentrations increase in the environment.
Many of these metals are among “the most notorious water pollutants and are known for their toxicity and environmental persistence [notamment dans les sédiments] », underlines the author. In addition, they would contribute to “forest dieback particularly in low pH conditions”.
Certain organic compounds emitted during pyrotechnic explosions, such as polycyclic hydrocarbons, are deposited on buildings, soils, bodies of water and plants. However, during extreme heat, these compounds volatilize again and are then transported further where they condense a second time. This phenomenon repeats until the compounds end up in cold regions, where they accumulate, such as in the Arctic, where high concentrations have been measured.
Once in water, these persistent organic pollutants (or POPs, as they are often called) concentrate in the fatty tissues of aquatic species and thus spread throughout the food chain. “Studies have even linked exposure to POPs to the decline, disease and abnormalities of certain wildlife species […]particularly the Great Lakes and their surroundings,” writes Gabrielle Lajoie.
Panicked birds
In addition to all this chemical pollution, the loud bangs and brilliant flashes of pyrotechnic displays can cause panic and desertion among birds, which may abandon their eggs or chicks which then become prey to predators or “die from lack of care.” , adds the researcher.
To address all these forms of pollution, some are starting to use less toxic chemical compounds. Still others are proposing sound and light shows with drone flights, which could undoubtedly prove just as spectacular! This year, the six shows presented by the countries competing at the International des Feux Loto-Québec will each include a five-minute portion using laser technology. “It’s the equivalent of a fireworks display that we’re replacing with these light shows [qui sont] an eco-responsible practice implemented with the firm Laser-Quantum,” argues the organizer of the competition on the La Ronde site.