Question

Which one of the following plume behaviours occurs when atmospheric inversion begins from the ground level and continues?

• A. Looping
• B. Fumigation
• C. Coning
• D. Fanning

Hint:

Remember the plume patterns: \[ \begin{array}{ll} \textbf{Looping} &\rightarrow \text{Highly unstable atmosphere} \textbf{Coning} &\rightarrow \text{Neutral atmosphere} \textbf{Fanning} &\rightarrow \text{Highly stable atmosphere} \textbf{Fumigation} &\rightarrow \text{Unstable below, stable above} \end{array} \]

Answer 1

The Correct Option is D

Concept: The behaviour of a pollutant plume depends on atmospheric stability. Different plume patterns are:
• Looping – Highly unstable atmosphere.
• Coning – Neutral atmosphere.
• Fanning – Highly stable atmosphere (temperature inversion).
• Fumigation – Unstable air below with stable air above.

Step 1: Understand atmospheric inversion. A temperature inversion creates a highly stable atmosphere that suppresses vertical mixing. As a result, the plume spreads mainly in the horizontal direction.

Step 2: Identify the plume behaviour. Since the inversion starts from the ground level and continues upward, the plume takes the shape known as \[ \boxed{\text{Fanning}.} \] Therefore, the correct option is \[ \boxed{(D)\;\text{Fanning}.} \]