THE CHEMISTRY BEHIND FIREWORKS
The bangs and fizzes of fireworks are rapidly replacing loud renditions of countdowns as the defining sound of New Year’s Eve celebrations around the world, with city landmarks – everything from the Palm Jumeirah to the Sydney Opera House to the Eiffel Tower in Paris – becoming stages for increasingly spectacular pyrotechnic displays. The bigger the psychedelic aerial displays, the better.
This year, the Burj Khalifa is doing away with a fireworks display and instead promising a light and laser show like no other to ring in the New Year. Brigadier Abdullah Ali Al Ghaith, director of the general department of organisations, protective security and emergency, has reportedly said that “lasers are safer than fireworks”. Fireworks, he said, are “old methods” and a light show is heralding a new era. Not to mention that by eliminating fireworks from the New Year’s Eve celebrations, Emaar and the Burj Khalifa are taking a major stance for environmental safety.
Here’s the thing: fireworks are nothing more than a pretty pollutant, and enjoying them means there’s an environmental price to pay. When fireworks light up the sky with dots, dashes, flashes and blooms of colour and brilliant white brightness; there is something mysterious at play. Different chemicals added to the basic ingredients produce different colours and sounds. For instance, barium salts makes green, while copper salts make blue, iron filings create a gold flutter effect and potassium benzoate burns in a rapidly oscillating manner creating a whistle noise. Fireworks are, essentially, all about chemistry.
Firework smoke is rich in tiny metal particles. These metals make firework colours, in much the same way as Victorian scientists identified chemicals by burning them in a Bunsen flame; so blue from copper, red from strontium or lithium, and bright green or white from barium compounds.
There is yet more smoke from potassium and aluminium compounds, which are used to propel fireworks into the air. Perchlorates are also used as firework propellants; these are a family of very reactive chlorine and oxygen compounds, which were used by Nasa to boost space shuttles at launch.
All this to say that fireworks can lead to substantial air pollution problems, not to mention that what goes up has to come down. Fireworks that fall to the ground contain residues of unburnt propellants and colourants, while particle pollution in the air eventually deposits on the ground or gets washed out by rain. Worldwide, firework pollution remains unchecked.
No fireworks at Burj Khalifa