How does the Gaussian plume model handle multiple receptors along the downwind line?

How does the Gaussian plume model handle multiple receptors along the downwind line?

• A. It computes the concentration at each receptor using the same downwind distance x but varying height z and lateral position y as needed.
• B. It uses unique downwind distances for each receptor.
• C. It ignores multiple receptors and uses a single line.
• D. It predicts only centerline concentration.

Answer: (A)

The Gaussian plume model treats concentration as a three‑dimensional field C(x,y,z) that evolves with downwind distance and spreads in the crosswind and vertical directions according to σ_y(x) and σ_z(x). When you have several receptors along the downwind line, you evaluate the concentration at each receptor’s location using the same distance from the source along the plume (the same x) but you input their specific lateral (y) and vertical (z) coordinates. The Gaussian terms exp(-y^2/(2σ_y^2)) and exp(-(z−H)^2/(2σ_z^2)) (plus the ground reflection term) then give each receptor its distinct concentration, even though the plume has advanced the same amount in the x direction. This mirrors how the plume’s spread depends on distance and how off-center and different heights experience the dilution differently. If receptors were at different x distances, you would use those respective x values; but for multiple receptors along a line at the same downwind distance, you simply sample the field at their individual y and z positions.

The Gaussian plume model treats concentration as a three‑dimensional field C(x,y,z) that evolves with downwind distance and spreads in the crosswind and vertical directions according to σ_y(x) and σ_z(x). When you have several receptors along the downwind line, you evaluate the concentration at each receptor’s location using the same distance from the source along the plume (the same x) but you input their specific lateral (y) and vertical (z) coordinates. The Gaussian terms exp(-y^2/(2σ_y^2)) and exp(-(z−H)^2/(2σ_z^2)) (plus the ground reflection term) then give each receptor its distinct concentration, even though the plume has advanced the same amount in the x direction. This mirrors how the plume’s spread depends on distance and how off-center and different heights experience the dilution differently. If receptors were at different x distances, you would use those respective x values; but for multiple receptors along a line at the same downwind distance, you simply sample the field at their individual y and z positions.