We had a huge fireworks show for the July 4th in DC. Only the first few minutes were visible though. There was not much wind and a thermal inversion so the smoke from each explosion left a cloud that obscured the next firework. The build up was so dense, it got to the point where we couldn't even see the glow from the fireworks behind the smoke. After 15 minutes, we gave up and headed home. On the walk back, we noticed it was getting foggy and by the time we reached our street, we realized it was not fog but smoke from the fireworks. You can see in the photos how bad the build-up got - according to air quality monitors, at that point we had the worst air quality in the nation.

Fireworks video 1
Fireworks video 2