Air Pollution MCQ with answer and solution

Concept

Indian National Ambient Air Quality Standards (NAAQS) give limits for PM10 (RSPM) in residential areas.

Step-by-step solution

1. RSPM means particles smaller than 10 µm (PM10). 2. Under the 2009 NAAQS, the PM10 limit for industrial, residential, rural and other areas is 60 µg/m³ (annual average) and 100 µg/m³ (24-hour average). 3. Under the older 1994 NAAQS, the RSPM limits for residential areas were 60 µg/m³ (annual) and 100 µg/m³ (24-hour). 4. Among the options, 60 µg/m³ matches the annual average limit.

Explanation

RSPM is PM10. In India the annual average limit for residential areas is 60 µg/m³. The 24-hour limit is 100 µg/m³, and it is not given in the options. So 60 µg/m³ is the best choice.

Why the other options are wrong

B (140 µg/m³): this is the older 1994 limit for industrial areas, not residential. C (200 µg/m³): this is the old limit for SPM in residential areas, not RSPM. D (360 µg/m³): this is the old SPM 24-hour limit for industrial areas.

Shortcut

Remember: RSPM (PM10) residential = 60 annual, 100 for 24 hour. SPM old residential = 140 annual, 200 for 24 hour.