The WHO Air Quality Guidelines (2021 update) revised the annual PM2.5 guideline value downward from 10 µg/m³ to:

• A 7 µg/m³
• B 5 µg/m³ ✓
• C 8 µg/m³
• D 12 µg/m³

Explanation

The WHO Global Air Quality Guidelines (2021) set the annual average PM2.5 guideline at 5 µg/m³ (reduced from the previous 10 µg/m³ set in 2005), reflecting accumulating evidence linking fine particulate matter exposure to cardiovascular disease, lung cancer, respiratory disease, and adverse birth outcomes at lower concentrations than previously recognized. The 24-hour mean PM2.5 guideline was revised to 15 µg/m³. India's National Ambient Air Quality Standards (NAAQS) permit an annual PM2.5 of 40 µg/m³, reflecting feasibility constraints rather than health-based targets.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.