Question

Which of the following are criteria pollutants under national ambient air quality standards?
A. PM\(_2.5\)
B. NO\(_x\)
C. Lead
D. Methane
E. Sulphur dioxide

• A. A, B and D only
• B. A, B and C only
• C. A, C and E only
• D. A, B, C and E only

Hint:

The main six criteria pollutants focused on globally are CO, Pb, NO\(_2\), O\(_3\), PM (PM\(_2.5\)/PM\(_10\)), and SO\(_2\). Methane is usually discussed in the context of climate change, not direct air quality standards.

Answer 1

The Correct Option is D

Step 1: Define "Criteria Pollutants".
Criteria air pollutants are a set of common air pollutants that are regulated by national environmental agencies because they can harm public health and the environment.

Step 2: List the criteria pollutants in India (under NAAQS).
India's National Ambient Air Quality Standards (NAAQS) regulate 12 pollutants: PM\(_10\), PM\(_2.5\) (A), Sulphur Dioxide (SO\(_2\)) (E), Nitrogen Dioxide (NO\(_2\)) (B, as part of NO\(_x\)), Ozone (O\(_3\)), Carbon Monoxide (CO), Lead (Pb) (C), Ammonia (NH\(_3\)), Benzene, Benzo(a)Pyrene, Arsenic, and Nickel.

Step 3: Evaluate the given options against the list. - A (PM\(_2.5\)), B (NO\(_x\)), C (Lead), and E (Sulphur dioxide) are all on the list. - D (Methane) is a major greenhouse gas but is not regulated as a criteria pollutant for direct ambient air quality in the same way. Conclusion: The correct combination from the options is A, B, C, and E.