Let's take a look at the health impact of fireworks.
What is in a firework?
A little strontium nitrate, a pinch of calcium sulfate, black powder, oxidizing agent, and binder and we are all set. A firework, or its smaller cousin, the firecracker, are products intended to go out with a bang and sometimes a burst of color. For as complicated as they look, the chemistry behind them is pretty understandable.
To delight the eye on the 4th of July, fireworks manufacturers pack a cardboard shell with black powder that boosts the shell skyward. A time-delay fuse from the powder burns through to the bursting charge at the right altitude. The bursting charge holds specially designed stars that are the heart of the colors and shapes you love to see go ka-boom.
As the bursting charge ignites, gases created by chemical reaction expand, heating metal salts packed in the shell. Those burning salts are the colors you see. The shell can be packed randomly to create an evenly dispersed display, or carefully arranged to create a flower, smiley face, or other shape.
But that is not all there is to it.
Some of the metal salts that create the colors you love, like orange, red, and blue, have a degree of toxicity when used in large amounts. The black powder that propels the shell, and ignites the bursting charge, is another story.
Sodium percchlorate is a primary component of rocket fuel, and the black powder used to make any exploding firework. While perchlorate is naturally present in the environment, it is more often produced through industrial processes needed for a number of chemical applications.
Along with chemical reactions aloft, shooting rockets into the sky seeds the atmosphere with chemical and cardboard debris. When fireworks go up, perchlorates and particulate rain down, causing problems below.
Should You Be Concerned About the Health Impact of Fireworks?
When fireworks displays are over, and cars and people make their way homeward, the fallout from the display is just beginning.
Perchlorates occur naturally, sometimes in the form of saltpeter used to make fertilizer. Oftentimes, perchlorates are located in and around hazardous waste sites. Perchlorate is considered a hazardous substance that can harm your health, although whether you suffer from exposure depends on a number of factors.
Because perchlorate is readily water soluble, it breaks down easily, leaching out of the ground where it falls, and into groundwater. Contaminated groundwater is used for irrigation, and remains behind in plants. Making its way up the food chain, or through inhalation, perchlorates find their way into the human body.
Although perchlorate clears the body through your bloodstream, kidneys, and urine, it is taken up in larger amounts in thyroid, breast, and salivary tissue. Perchlorate has an active impact on the thyroid in the following ways:
- Perchlorate reduces uptake of iodine needed for synthesis of proper levels of thyroid hormone
- Extended exposure to perchlorate could lead to diminished thyroid capacity and hypothyroidism
- Diminished production of thyroid hormone has a cascading effect throughout the body
- Infants and children are more susceptible to damage from perchlorate toxicity, perchlorate is shown to pass through breast milk
Studies show fine particle matter effects respiratory health of people of all ages. To start a conversation about particulate matter (PM) and public health, researchers from the National Oceanic and Atmospheric Administration (NOAA) surveyed atmospheric PM levels in the days surrounding July 4th, between the years 1999 and 2013. Highlights of their findings include:
- Increase in atmospheric particulate matter is dependent on proximity to firework displays
- While some areas saw a 42 percent increase in PM, one site in a field adjacent to a firework display showed a 370 percent increase in fine PM
- High particulate levels are typical in the day and evening before July 4, and dropped by noon on July 5.
The spike in PM is grandfathered into Environmental Protection Agency (EPA) rules for atmospheric particulate due to the tradition of fireworks displays across the country. However, potential impact of high PM levels include:
- Premature death can be caused by inhalation of fine particles that exacerbate inflammation, and cardiac symptoms leading to heart attack, or stroke
- Inhalation of PM can cause or trigger asthma, or worsen conditions related to diminished lung capacity
- Long term exposure to PM is associated with reproductive difficulties, low birth weight, and infant mortality
The EPA recommends people and children with respiratory concerns try to view fireworks displays from upwind, or at a distance. Those with asthma should have medication on hand in case of breathing difficulty.
Greener Fireworks in the Future?
With heightened awareness of the health and environmental impact of traditionally manufactured fireworks, some vendors are moving forward with so-called green fireworks. In November of 2014, China, the birthplace of fireworks, staged an environmentally friendly fireworks display as host of the Asia-Pacific Economic Cooperation forum (APEC).
The fireworks show was entitled "Nature Song," and was supposedly free from metal-based and other harmful chemicals. Despite the claim, air quality data was not made available after the show.
Fireworks and apple pie, nothing is more traditional on the Fourth of July. This summer consider standing upwind.