Fireworks are a Fourth of July favorite, but a new nationwide study finds they also pollute the air and could cause breathing problems and other serious health complications for some Americans.
The study, published in the journal Atmospheric Environment, used observations taken from 315 air quality monitoring sites around the U.S. between 1999 and 2013. Without fail, the researchers found that from around 9 to 10 p.m. each Independence Day, concentrations of fine particulate matter, or PM2.5, surged, teetering on the edge of the upper limit of what the EPA considers to be safe (and in some locations, wildly surpassing it). Things got back to normal by around noon the following day, they found, but for 24 hours beginning around 8 p.m., PM2.5 levels were 42 percent higher than usual.
While scientists have known for years that fireworks displays produce a surge in fine particulate matter, the new study is the first nationwide quantitative analysis of the effects. “These results will help improve air quality predictions, which currently don’t account for fireworks as a source of air pollution,” said lead author Dian Seidel, a scientist at the National Oceanic and Atmospheric Administration.
All fireworks contain carbon (a fuel), sulfur (an accelerant) and potassium nitrate (an oxidizer), which are necessary for burning. Additionally, a variety of chemicals — arsenic, manganese, aluminum, and barium nitrate, to name a few — are added during the manufacturing process to act as stabilizers, and to create the dazzling colors and effects that crowds love. When ignited, fireworks release an array of pollutants, including high levels of sulfur dioxide (SO2), carbon dioxide (CO2), carbon monoxide (CO), and particulate matter (PM), as well as several metal salts, like aluminum, manganese, and cadmium.
Both long- and short-term exposures to these pollutants are linked to a range of health effects — from coughing, wheezing and shortness of breath, to asthma attacks, heart attack and stroke, to even premature death in people with heart or lung disease. In past studies, researchers have found a significant uptick in hospitalizations for respiratory distress in the 24-48 hours after fireworks displays in Hawaii and numerous sites across Asia. There are also limited case reports of fatal and near-fatal asthma attacks within hours of exposure to fireworks.
This latest study did not specifically look for any resulting effects on health. However, in response to the research, the EPA cautioned that children, older adults, and people with heart disease, asthma or other lung diseases are particularly sensitive to particle pollution. The agency recommended that they limit their exposure by watching fireworks from a distance and, if possible, from upwind. People with asthma should also carry their quick relief medicine with them to any fireworks shows, the EPA said.