Which factor most directly influences the vertical dispersion of smoke?

Which factor most directly influences the vertical dispersion of smoke?

• A. Wind Speed
• B. Temperature
• C. Atmospheric Stability
• D. Relative Humidity

Answer: (C)

Atmospheric stability governs how easily air parcels rise or are suppressed, and that directly controls how far smoke can mix vertically. In stable conditions, vertical motions are damped, so the plume stays relatively low and tends to spread more horizontally, concentrating smoke near the ground. In unstable conditions, buoyant air rises and turbulence increases, boosting the vertical mixing and making the plume rise higher and disperse more through the column. Wind speed influences how far the plume travels horizontally, but the key factor for vertical spread is how stable the atmosphere is. Temperature relates to stability through how it changes with height, but it’s stability itself that dictates vertical dispersion. Relative humidity mainly affects moisture but not the primary vertical mixing of smoke.

Atmospheric stability governs how easily air parcels rise or are suppressed, and that directly controls how far smoke can mix vertically. In stable conditions, vertical motions are damped, so the plume stays relatively low and tends to spread more horizontally, concentrating smoke near the ground. In unstable conditions, buoyant air rises and turbulence increases, boosting the vertical mixing and making the plume rise higher and disperse more through the column. Wind speed influences how far the plume travels horizontally, but the key factor for vertical spread is how stable the atmosphere is. Temperature relates to stability through how it changes with height, but it’s stability itself that dictates vertical dispersion. Relative humidity mainly affects moisture but not the primary vertical mixing of smoke.