DC's 850,000-Fireworks Display Drove Air Pollution to Unhealthy Levels Across Entire City

All 26 air quality sensors deployed citywide by Clarity Movement registered EPA "unhealthy for sensitive groups" levels after Freedom 250's July 4 fireworks display. Particulate matter spiked to 6.7 times pre-event concentrations, peaking at 4am Sunday—five hours post-display, reflecting overnight smoke accumulation. The 850,000-firework show from ten sites explains why unhealthy readings appeared uniformly across DC rather than near launch zones alone.