In a region where radiation inversions extend beyond the stack height, the emitted plume will be best characterized as:

Correct option is B

Radiation Inversions:
· A radiation inversion occurs when the air near the ground is cooler than the air above it, leading to a stable atmospheric condition.
· This prevents vertical mixing of air, trapping pollutants in a narrow layer.
Fanning Plume:
· In the presence of radiation inversions that extend above the stack height, the emitted plume spreads horizontally rather than vertically, resembling a fan.
· This occurs due to the stable atmosphere limiting vertical dispersion.
Other Plume Types Explained:
· (a) Coning: Occurs in neutral atmospheric conditions, where vertical and horizontal dispersion are equal, resulting in a cone-shaped plume.
· (c) Trapping: Happens when there are two inversion layers, one above and one below the plume, trapping it in between.
· (d) Looping: Seen in unstable atmospheric conditions with vigorous vertical mixing, leading to a wavy plume shape.
Information Booster: 1. Plume Behavior:
· Determined by atmospheric stability, wind speed, and temperature gradients.
2. Fanning:
· Common during nighttime or early morning when radiation inversions are strong.
3. Air Pollution Impacts:
· Fanning plumes can result in concentrated pollutant levels near the ground, impacting air quality.
4. Control Measures:
· Increasing stack height or using pollution control equipment to disperse pollutants more effectively.