GATE CE 2018 Set 2 — Question 25

MCQ+1 / -0.33MediumGaussian Plume ModelAir PollutionEnvironmental Engineering

Environmental Engineering → Air Pollution → Gaussian Plume Model

Last updated 5 September 2026

Question

In the figures, Group I represents the atmospheric temperature profiles (P, Q, R and S) and Group II represents dispersion of pollutants from a smoke stack (1, 2, 3 and 4). In the figures of Group I, the dashed line represents the dry adiabatic lapse rate, whereas the horizontal axis represents temperature and the vertical axis represents the altitude. The correct match is

Correct answer (A) P-1, Q-2, R-3, S-4 Solution The matching is based on atmospheric stability and plume behavior: P (Superadiabatic) : Environmental Lapse Rate (ELR) > Dry Adiabatic Lapse Rate (DALR). This is a highly unstable condition leading to a Looping plume (1). Q (Adiabatic) : ELR = DALR. This is a neutral condition leading to a Coning plume (2). R (Inversion) : Temperature increases with altitude (negative lapse rate). This is a very stable condition leading to a Fanning plume (3). S (Inversion over superadiabatic) : A stable layer exists above an unstable layer. Pollutants are prevented from rising and are mixed downwards, leading to Fumigation (4). Thus, the correct match is P-1, Q-2, R-3, S-4. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (A) P-1, Q-2, R-3, S-4 Solution The matching is based on atmospheric stability and plume behavior: P (Superadiabatic) : Environmental Lapse Rate (ELR) > Dry Adiabatic Lapse Rate (DALR). This is a highly unstable condition leading to a Looping plume (1). Q (Adiabatic) : ELR = DALR. This is a neutral condition leading to a Coning plume (2). R (Inversion) : Temperature increases with altitude (negative lapse rate). This is a very stable condition leading to a Fanning plume (3). S (Inversion over superadiabatic) : A stable layer exists above an unstable layer. Pollutants are prevented from rising and are mixed downwards, leading to Fumigation (4). Thus, the correct match is P-1, Q-2, R-3, S-4.

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