The Fourth of July fireworks display in the capital impacted the amount of fine particulate matter in the atmosphere.

Internal National Park Service documents seen by The Washington Post suggest visitors should “avoid prolonged exposure” in unhealthy areas

A draft air-quality analysis conducted using NPS modeling warns that individuals should “avoid prolonged exposure” to the pollution following the display.

A severe heatwave has disrupted Fourth of July celebrations across the central and eastern United States, forcing cancellations of parades, concerts, and fireworks.…

The oppressive heat also altered celebrations in Philadelphia, where temperatures were expected to reach 99 degrees.