What is the correct increasing order of the following 24-hour pollutant limits…
2023
What is the correct increasing order of the following 24-hour pollutant limits prescribed by CPCB for residential areas?
A. Suspended Particulate Matter (SPM)
B. Respirable Suspended Particulate Matter (RSPM)
C. Lead (Pb)
D. Ammonia (NH3)
Choose the correct answer from the options given below:
Answer: D. C, B, A, D — ConceptAmbient pollutant limits expressed in different units can be compared only after conversion to one common unit. For an increasing order, convert every…
- A.
A, B, C, D
- B.
B, A, C, D
- C.
C, D, B, A
- D.
C, B, A, D
Show answer & explanation
Correct answer: D
Concept
Ambient pollutant limits expressed in different units can be compared only after conversion to one common unit.
For an increasing order, convert every 24-hour limit to micrograms per cubic metre and then sort the numerical values from smallest to largest.
Application
Lead (Pb): 1.0 µg/m3.
Respirable suspended particulate matter (RSPM): 100 µg/m3.
Suspended particulate matter (SPM): 200 µg/m3.
Ammonia (NH3): 0.4 mg/m3 = 400 µg/m3.
Cross-check
In one common unit, the consecutive values increase as 1.0 < 100 < 200 < 400, so every adjacent comparison is increasing.
Result
The increasing order is Lead < RSPM < SPM < Ammonia.