Pollution is fireworks’ dirty little secret

Also, traces of poisonous metals, which give fireworks their bright colours, and perchlorate, a hormone-altering substance used as an oxidiser, trickle to the ground, contaminating waterways. One Environmental Protection Agency study found that perchlorate levels in an Oklahoma lake in the US rose 1,000-fold after a fireworks display, and they stayed high in some areas for up to 80 days.

European chemists Georg Steinhauser and Thomas Klapotke wrote in a recent scientific journal that “several poisonous substances are known to be released in the course of a pyrotechnic application” and that they are dispersed over a large area.

“It is clear from a vast array of studies that traditional pyrotechnics are a severe source of pollution,” they wrote.

The black powder, or gunpowder, used in most fireworks has an extremely high carbon content, and when ignited, it fills the air with fine particles capable of inflaming airways and lodging in lungs.

Particulates can cause coughing, sore throats and burning eyes. For people with asthma or other respiratory or cardiovascular conditions, the effects are much worse: hospital admissions and deaths from asthma attacks, heart attacks and respiratory disease increase whenever particulate levels rise. Next to fireworks displays, particulate levels increase about 100-fold.

Ironically, green-coloured fireworks are the least “green” because the metal that produces the colour, barium, is highly poisonous. Scientists in India found that airborne barium increased by a factor of 1,000 after a huge fireworks display there. Strontium, which creates red, and copper, which forms a blue hue, also can be toxic.

“The use of heavy metals like barium or strontium should be reduced or, if possible, avoided,” said Karina Tarantik, a University of Munich chemist whose lab is working on cleaner pyrotechnics.

Much of the new research has been propelled by concern over perchlorate, which has been used since the 1930s to provide oxygen for pyrotechnic explosions. Perchlorate, which has contaminated many drinking water supplies from military and aerospace operations, can impair the thyroid gland by blocking the intake of iodide. Fetuses are most at risk, since thyroid hormones regulate their growth.

Scientists have made significant advances in low-smoke and perchlorate-free technologies, prompted by the military, which uses flares and other pyrotechnics, and by the Walt Disney Co., which stages about 2,000 fireworks displays a year.

In the late 1990s, the Walt Disney Co. approached the Los Alamos National Laboratory with a request to develop cleaner fireworks to reduce smoke at Disneyland, which was prompting complaints to the AQMD from neighbors in Anaheim, California.

Instead of carbon-based materials, scientists there experimented with nitrogen atoms, which produced far less soot and smoke.

Based on those experiments, Los Alamos chemists Michael Hiskey and Darren Naud took an entrepreneurial leave and founded DMD Systems. Their fireworks use nitrocellulose, which is inexpensive and plentiful, and they emit water, nitrogen and carbon dioxide instead of smoke and perchlorate, Hiskey said. The metal content also has been reduced by about 90 percent, he said.
-Marla Cone (LAT-WP)