"Hourly concentrations of particulate matter rose to 6.7 times their pre-fireworks levels, according to an analysis"

"Washington DC residents breathed in “unhealthy” air for hours after a 40-minute Independence Day fireworks show over the National Mall on Saturday night, with the country’s capital briefly recording the worst air quality of any major city in the world.

The highly emitting display, which the president called “spectacular”, came as the Trump administration rolls back an unprecedented number of pollution controls.

Hourly concentrations of particulate matter rose to 6.7 times their pre-fireworks levels, according to a Tuesday analysis from the company Clarity Movement based on its network of 26 air quality sensors throughout the city in partnership with the local department of energy and environment. Every one of those sensors reached air quality levels which the Environmental Protection Agency deems “unhealthy for sensitive groups” during the event, the researchers found, with some recording even worse levels of emissions.

Levels of particulate matter peaked at 4am on Sunday, approximately five hours after the display concluded, according to the new analysis. It remained elevated for approximately five hours after reaching its peak, the authors found, with city officials issuing a Code Red alert."

Dharna Noor reports for the Guardian July 7, 2026. [2]