WASHINGTON, D.C. — The United States is scheduled to mark its 250th anniversary on July 4, 2026, with celebrations in Washington, D.C., that include a fireworks display. This event is projected to coincide with extreme heat and air quality concerns.

Washington, D.C., is expected to launch 850,000 fireworks in 40 minutes from 10 locations around the city on July 4, 2026. This display aims to set a new Guinness World Record for the largest fireworks display, surpassing the current record of 810,904 fireworks set during a New Year's Eve celebration in the Philippines in 2016. The Washington, D.C. display is approximately 10 times larger than the Macy's Fourth of July Fireworks Show in New York.

The week of July 4, 2026, is forecast to bring triple-digit temperatures to more than 50 million people, with at least 100 maximum temperature records projected, primarily on the East Coast. A high-pressure area, known as a heat dome, is located over much of the United States, limiting winds and trapping hot air near the ground. Washington, D.C., is expected to reach approximately 102 degrees Fahrenheit on July 4, 2026, which would make it the city's hottest July 4 in history.

Heat can worsen the persistence of air pollution from fireworks, which typically generate smoke pollution that can last for several hours. In some cities, air quality often does not return to normal until around noon the day after fireworks displays. Heat also creates ground-level ozone before fireworks are launched in some urban areas. Ground-level ozone typically forms when chemicals from vehicle exhaust react under strong ultraviolet rays on hot days. Washington, D.C., is forecast to experience at least moderate amounts of ground-level ozone during the day on July 4, 2026.

Dan Jaffe, a professor of environmental chemistry at the University of Washington, stated that chemicals from fireworks particles persisting until the next day could react with sunlight and increase ozone risk on July 5, 2026. He noted that hotter cities tend to have worse ozone pollution. "Sabemos que todas las ciudades del país en las que se celebran espectáculos pirotécnicos registran niveles altísimos de partículas en suspensión en cuanto comienza el espectáculo," Jaffe said. "Las emisiones van a tener importancia. Cuantos más fuegos artificiales haya, más PM 2,5 habrá en el aire." He added, "El calor exacerba todo este problema, por lo que generalmente vemos los niveles más altos de ozono cuando las temperaturas llegan a las altas temperaturas de 80 y 90 en la mayoría de los lugares." Jaffe also said, "Si piensas en una franja de ciudades en los EE.UU., generalmente las ciudades más cálidas tienden a tener peor contaminación por ozono."

Why It Matters

Fireworks release PM 2.5 particles, microscopic pollutants known to cause respiratory problems and worsen heart conditions. Some of these particles contain metals that create firework colors and can lead to irritation, coughing, or shortness of breath. Researchers found an increase of approximately 42 percent in PM 2.5 pollutants in the hours following a fireworks display. The combination of fireworks emissions and meteorology could result in elevated air pollution levels in Washington, D.C., during the celebrations.