GATE 2026 ES – Question 39
Match CPCB continuous ambient monitoring pollutants P $SO_2$ (µg/m³),Q $NO_2$ (µg/m³),R $PM_{2.5}$ (µg/m³),S CO (mg/m³) with methods (i) Chemiluminescence,(ii) Non-dispersive infrared spectroscopy,(iii) Ultraviolet fluorescence,(iv) Beta attenuation. Options list P, Q, R, S.
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Correct answer: (C) iii, i, iv, ii
Explanation
SO₂ is measured by ultraviolet fluorescence; NO₂ by chemiluminescence after conversion to NO; PM₂.₅ by attenuation of beta radiation through collected particles; CO by non-dispersive infrared absorption. Thus P–iii, Q–i, R–iv, S–ii, and **C**.