The National Park Service will set off more than 850,000 fireworks into the skies over Washington on Saturday to commemorate the nation’s 250th anniversary, illuminating the nation’s capital with a blast of patriotic light.
Then the fallout occurs.
Scientists have well-documented the soot and heavy metal pollution that can spike dramatically after fireworks displays, and experts say the world record-setting number of fireworks scheduled for July 4 means a similarly large pollution spike. According to the National Park Service, only 7,000 fireworks were set off in Washington last year. Multiplying this by 120 also means that water pollutants such as perchlorate and heavy metals could be deposited in the Potomac River, and the effects on humans and the environment are not yet well understood by scientists.
“I wish we had a team in Washington, D.C., to do all this,” said Terry Gordon, a semi-retired research professor at New York University’s Grossman School of Medicine.
By “this much” he is referring to a study he conducted three years ago. The study had more than a dozen students run around New York to sample air and water before and after the Macy’s fireworks show on the Fourth of July (a “friendly” police officer was needed for access to the East River).
The results were amazing. Two of the company’s air samplers saw particulate matter (soot and smoke particles small enough to be inhaled into lung tissue and into the bloodstream) rising from a range of 10 to 15 micrograms per cubic meter to more than 1,000 micrograms per cubic meter. A third site had more than 3,000 micrograms. The 24-hour national standard set by the EPA is 35 micrograms, but the annual average is only 9 micrograms.
Researchers recorded a significant spike in air pollution hours after the Macy’s Fourth of July fireworks in New York on July 4, 2023. Yuki Iwamura/AP
In 2023, 60,000 fireworks were set off at Macy’s. In Washington, 851,000 lights will illuminate the sky, more than 14 times as many.
Gordon said she had hoped to learn about this year’s Washington festivities, but most of the students had graduated and she thought access would be impossible due to the city’s heavy security.
“This upcoming event is a great natural experiment to see what happens,” said David Ruglio, one of Gordon’s students who participated in the Macy’s study and now a postdoctoral researcher at Tulane University. “I mean, you can’t imagine what 800,000-plus fireworks would do to air quality.”
The good news is that dirty air doesn’t linger for very long. One study found that particulate matter from July 4 fireworks remained elevated at 315 different monitoring sites for about 24 hours. On average, fireworks displays increased pollution by 42%. However, fireworks contamination dissipates after a day and is usually blown away or deposited in water or soil within a day.
“The question is: Are they just as toxic or more toxic than the regular old fossil fuel combustion particles that you might breathe in day in and day out?” Gordon said, referring to common sources of pollution such as vehicles and power plants. “That’s unclear.”
The National Park Service and Freedom 250, a Trump-aligned group that helps plan the event, did not respond to requests for comment. In response to a question about a possible spike in air pollution, EPA spokesman Mike Bastash said Washington state has jurisdiction over urban air quality.
“First of all, fireworks are amazing, and we hope everyone enjoys a great show in and around our nation’s capital as we celebrate America’s 250th anniversary,” Bastash said in an email. “EPA has not issued a fireworks permit for this event.”
Washington isn’t the only city to step up its fireworks display this year. Nashville is preparing for the biggest celebration in history, and San Francisco plans to launch fireworks from the Golden Gate Bridge for the third time in history, according to the American Fireworks Association. Mount Rushmore will also host an elaborate fireworks display for the first time since 2020.
This year’s festival coincides with a severe drought in Washington and 100-degree temperatures Thursday through Saturday. Washington-based utility DC Water is working with the federal government to ensure water is available in the event of a fire, as residents have been known to set off their own fireworks.
“Our incident management team is preparing to monitor the situation and will be activated leading up to Independence Day. Field staff will be strategically positioned and will respond as needed,” DC Water spokeswoman Shelley Lewis said in an email.
Unlike in recent years, fireworks won’t just be on the National Mall. Some will also be shot from eight barges on the Potomac River and from West Potomac Park.
Tyler Frankel, an associate professor of environmental science at the University of Mary Washington, said the drought means pollutants can linger in the Potomac River longer than under normal conditions. In the river near Theodore Roosevelt Island, pollutants can easily become trapped due to the “tidal slosh” phenomenon in which water flows both upstream and downstream, Frankel said.
Amphibians and juvenile fish are particularly vulnerable to perchlorate. Perchlorate is a compound used in fireworks to cause rapid combustion, but it can also interfere with developmental processes in animals.
“Even though we’ve had some significant rainfall, we’re still in drought conditions,” Frankel said. “The idea is to flush this material downstream to reduce its concentration and reduce its impact, but the time it takes for that to happen is being extended.”
Other animals at risk include the osprey, an iconic fish-eating bird that is currently in the midst of its breeding season and is easily startled by loud noises.
The Chesapeake Bay region is home to 20 percent of the world’s ospreys, but their numbers have declined in recent years, said Joanie Millward, executive director of the Virginia Osprey Foundation. Millward said startled ospreys often flee their nests when fireworks go off, putting their young at risk of being eaten by predators.
“At best, it’s extremely stressful. At worst, it can lead to death,” she says.
An osprey tends to its nest in the Potomac River. | J. Scott Applewhite/Associated Press
Health risks and ‘soaring pollution’
Fireworks also rain down small but potentially potent amounts of heavy metals, which are used to create bright colors but can pose serious health risks.
A study conducted by Gordon in 2020 found that exhaust fumes from some types of fireworks sold to individuals for home use contained “alarming amounts” of lead. The majority of products sold in 2025 were consumer fireworks, with nearly 300 million pounds of “display” fireworks compared to 23.5 million pounds, according to the American Pyrotechnics Association. Overall fireworks consumption has more than doubled in the past 25 years.
The impact of fireworks on air quality around the world has been well researched, from Diwali in India to summer religious festivals in Malta to Guy Fawkes Day celebrations in New Zealand. However, little is known about the subsequent public health effects.
No one has yet conducted an epidemiological study to determine whether hospitalizations for asthma or other cardiovascular or respiratory conditions increase after fireworks displays. There have been no studies like the ones being done on wildfire smoke and environmental pollution.
Several years ago, Gordon unsuccessfully sought a grant from the National Institutes of Health to do just that. But interest appears to remain. Government officials contacted Gordon last week to ask whether such a study was possible. He declined to identify anyone or even identify the agency for fear of retaliation.
“We were accused of being so unpatriotic,” Gordon said of the Macy’s fireworks investigation. “And it was the other way around. … We all love fireworks. That’s why we gave our newspapers all sorts of funny names.” (What title did they decide on? “Surge in Pollution”)
Experts say there are several steps people can take to protect themselves from fireworks-related pollution.
Observing the show from further away reduces exposure. So is staying indoors and keeping windows closed. Indoor air filters scrape out particles. And all the N95 masks left unused during the pandemic will also be effective.
But for people with underlying health conditions, that’s not always enough.
“The 250th celebration is exciting, and we don’t want to deny that for a second,” says Laura Kate Bender of the American Lung Association. “But as the number of fireworks increases, so does the health risk. As the show gets bigger, so does the amount of smoke in the air.”
Sam Schmitz knows that all too well. Schmitz, a Mama’s Clean Air Force organizer who also has asthma, spent last July 4th “indoors wearing a mask, leaning against an air purifier, struggling to breathe, trying to figure out if I needed to go to the hospital.”
Past Fourth of July celebrations sent her to the emergency room, so she’s not taking any chances with this year’s exponentially larger fireworks display. She booked a hotel room in Gaithersburg, Maryland, hoping to escape the smoke safely.
“I thought about going to New York or Baltimore, where I have friends who would celebrate with me, but since it’s the 250th anniversary, I’m worried that there will be fireworks in all the major cities this year,” she said.
