Reason (R) : The ground level concentration varies inversely proportional to the height of the stacks.
Codes :
Stack Height and Ground Pollutant Concentration
This section evaluates the relationship between industrial stack height and ground-level pollutant concentration.
Assertion: Stack Height Reduces Ground Concentration
Assertion (A): Ground level concentration of pollutants decreases when taller stacks are used.
This assertion is true. Taller stacks release pollutants at higher altitudes. This greater height allows atmospheric dispersion (mixing with air due to wind and turbulence) to reduce pollutant concentration effectively before reaching ground level. This is a key principle in managing industrial emissions.
Reason: Proportionality Claim Accuracy
Reason (R): The ground level concentration varies inversely proportional to the height of the stacks.
This reason is false. Although pollutant concentration at ground level generally decreases as stack height ($h$) increases, the relationship is not a simple mathematical inverse proportion (where concentration $C \propto 1/h$). Real-world dispersion is complex, influenced by factors like plume rise, atmospheric stability, wind speed, and distance from the source. Dispersion models often show concentration related to inverse powers of height, like $C \propto 1/h^n$ ($n > 1$), or use more complex formulas.
Final Conclusion
Based on the analysis, Assertion (A) is factually correct, while Reason (R) presents an oversimplified and inaccurate mathematical relationship. Therefore, the correct option states that (A) is true and (R) is false.
Important Questions from Environmental Pollution and Control
A tributary flowing at a rate of 4 m3/s converges into a river flowing at a rate of 8.0 m3/s. The concentration of a pollutant 'X' at the upstream of the tributary before convergence was 12 mg/L and that of the river was 30 mg/L. If the pollutant X is completely mixed in the downstream, what would be its concentration?
Consider Gaussian-point source dispersion model with effective stack height H and dispersion coefficient σz = \(\frac{H}{\sqrt2}\). If the effective stack height H increases by 10%, the downwind ground-level concentration of pollutants would
In the two lists given below, List I provides the list of Pollutants, while List II indicates Health Effects. Match the two lists and choose the correct answer from the code given below :
List - I
(Pollutant)
List - II
(Health Effect)
(a) SO2 (i) Nerve and blood effects (b) O 3 (ii) Bronchitis
(c) CO
(iii) Asphyxiant (d) Pb
(iv) Pulmonary injury The online monitoring technique for NOx is based on the Chemiluminiscence of which of the following molecules in excited state?
A 500 MW coal based power station is operating at an efficiency of 30%. If the coal has 1% of sulphur content and 1 tonne of coal produces 8000 kWh energy, how much SO2 will be emitted daily by the plant?
