The fireworks spectacular in Washington that celebrated 250 years of American independence also blanketed the capital city with unhealthy air, according to a company that provides air testing services.
Pollution in the form of fine particulate matter — tiny particles that can contribute to asthma, heart disease and other ailments — peaked in the early morning at more than six times normal levels in the city, and the poor air quality remained for roughly five hours after the display concluded, according to an analysis by Clarity Movement, an air monitoring firm that analyzed data from 26 sensors operated by the city government.
Pollution levels started to rise Saturday evening, as fireworks set off by individuals began to degrade air quality in the capital, according to the Clarity analysis. Once the Freedom 250 display began around midnight, it created a “spike,” pushing the network’s average air-quality index for fine particulate matter, or PM 2.5, past the Environmental Protection Agency’s threshold for “unhealthy” air.
President Trump had promised that the 40-minute display would be “the largest fireworks show in history,” with some 850,000 pyrotechnics.
Two sensors placed near the National Mall reached levels considered “very unhealthy,” and all but one monitor reached the threshold considered unhealthy for all people, not just sensitive groups like older adults or people with respiratory conditions.
The plume was not spread evenly. At the peak of the pollution, around 5 a.m., the city was broadly covered by “unhealthy” air, the company said. By 8 a.m. the pollution began to dissipate, but air quality in neighborhoods to the north of the city remained poor while areas to the south and east of the city gradually returned to normal.
The analysis also found that airborne magnesium, a metal used to create bright white flashes in fireworks that can irritate skin and lungs, increased by more than 9,000 percent.
Before the fireworks show, the National Park Service had conducted its own analysis of the potential effects on air pollution. It found that air quality would be “hazardous” near the National Mall during and after the show and “very unhealthy” in downtown Washington, Capitol Hill and across the Potomac River in Arlington, Va., according to a copy of the analysis reviewed by The New York Times.
The Park Service also projected that fine particulate matter could drift as far as 15 miles downwind of the event, depending on the weather conditions. The Park Service did not release those estimates to the public, an omission that current and former Park Service employees called unusual.
Representatives for the Interior Department, the parent agency for the Park Service, didn’t immediately respond to a request for comment.
The American Lung Association warns that inhaling firework smoke is “detrimental to health.” The latest State of Global Air report, an annual study tracking air quality and research, found that air pollution killed nearly eight million people globally in 2023.
Danielle Alvarez, a spokeswoman for Freedom 250, the Trump-aligned organization responsible for much of the July 4 celebrations in the city, said “we will never apologize for honoring all those who made our 250th possible.”
Maxine Joselow contributed reporting from Washington.
