When the rockets and bombs burst in air tonight, spectators will experience more than a spectacular show celebrating America’s birthday.
Chemists say fireworks are the dirtiest of the dirty bombs: When their blends of black powder, metals, oxidizers, fuels and other toxic ingredients are ignited, traces wind up in the environment, often spreading long distances and lasting for days, even months.
Although pyrotechnic experts are developing environmentally friendly fireworks, Fourth of July revelers this year will be watching essentially the same, high-polluting technology that their grandparents experienced decades ago.
Public health officials warn that people with heart problems or respiratory diseases, such as asthma, should avoid the smoky celebrations, staying upwind or indoors.
“I enjoy a fireworks display as much as anyone else but we do have concerns about exposure to high levels of smoke and particles,” said Jean Ospital, health effects officer for the South Coast Air Quality Management District.
Also, traces of poisonous metals, which give fireworks their bright colors, and perchlorate, a hormone-altering substance used as an oxidizer, trickle to the ground, contaminating waterways. One Environmental Protection Agency study found that perchlorate levels in an Oklahoma lake 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.
Near fireworks displays, particulate levels increase about 100-fold and don’t return to normal until around mid-day on July 5, according to AQMD monitoring data.
Ironically, green-colored fireworks are the least “green” because the metal that produces the color, 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.
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.