Mixing Ceiling

The mixing ceiling is how high pollution can rise before it gets trapped. Think of it like an invisible lid on the city.

Low ceiling = pollution concentrates near the ground (worse air quality)

High ceiling = pollution disperses upward (better air quality)

The ceiling rises during the day as the sun heats the ground, and drops at night as the air cools. Cold, calm winter nights often have the lowest ceilings.

Wind Bar

The bar on the right shows wind speed at different heights. Each row shows:

• Condition — Stagnant, Breezy, Windy, or Storm
• Speed — in km/h

Stagnant air lets pollution accumulate whereas strong winds below the mixing ceiling are what actually clear the air — they blow pollution away and mix in fresh air from outside the city.