This Sunday, people around the world celebrated Chinese New Year with firework displays and sparklers, but new research confirms this tradition could seriously harm peoples health. An international team of scientists have shown that a firework display, even a small one at home, can spread toxic particles for miles.
Dr Zongbo Shi, a NERC fellow at the University of Birmingham who co-authored the study, says 'We compared particles directly emitted from firecrackers with airborne particles from the regional pollution haze during the 2011 Chinese New Year. It has confirmed for us that the pollution was from fireworks.'
The particles can seriously aggravate respiratory conditions, like asthma.
The study, published in Science of the Total Environment, used air monitoring equipment and microscopes to match toxic particles where fireworks were set off, to particles found more than 30 miles (50km) away.
The particles toxicity stems from the metals used to give fireworks their colour. These include barium which is used in rat poison but makes fireworks green, and strontium which makes them red.
Some fireworks mix several of these metals together to achieve the right hue, and when they explode, particles are scattered across the wider landscape.
'It's possible that fireworks without colours would be less toxic,' says Shi. 'But that's not what people want; they want colours.'
For anyone who's seen a firework display, it may seem obvious that the explosion releases particles and smoke into the atmosphere. But until now scientists didn't know how far-reaching the consequences may be. This is the first study to confirm that pyrotechnics cause a regional haze after big displays.
The use of toxic metals in fireworks is currently unregulated, although the Chinese Environmental Protection Bureau has banned the use of fireworks in the very centre of major cities like Shanghai and Beijing. Previous reports show particle levels in Beijing were fifty times greater than normal during a display and Shi believes the ban may now need to be be reconsidered, as a display in the city could seriously affect the surrounding rural areas.
The study may have consequences for much more than just Chinese New Year. Traditional bonfire night displays and Olympic ceremonies may need to scale back their firework use. The London 2012 organisers used hundreds of fireworks at last summer games, but the International Olympic Committee has said they may consider a more environmentally friendly laser show in future.
'There are on-going discussions about regulating firework displays,' concludes Shi. 'But are we really going to risk people's health for the sake of half an hour of thrill?'
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Li, W. et al. 2013. Indivivudal metal-bearing particles in a regional haze caused by firecracker and firework emissions. Science of the Total Environment, 443, 464-460, doi: 10.1016/j.scitotenv.2012.10.109