Revised National Ambient Air Quality Standards (NAAQS) 18th November, 2009

Practice Previous Exam Questions:

 1. PM2.5 concentrations in ambient air can be measured using (GATE 2022)

(A) Beta attenuation method

(B) Chemiluminescence method

(C) Gravimetric method

(D) Non dispersive infrared spectroscopy method

Answer:  (A) Beta attenuation method and (C) Gravimetric method

2. The 24 Hour National Ambient Air Quality Standard for PM2.5 in India is 

(A) 20

(B) 50

(C) 60

(D) 75

Answer: (C) 60