National Ambient Air Quality Standards

A one-year study by IIT-Kanpur has been sanctioned to review the national ambient air quality standards (NAAQS). This has been revealed by a RTI reply from Central Pollution Control Board (CPCB).

What is the need for review?

• Demand from various quarters —
  • • India had last revised its National Ambient Air Quality Standards in 2009.
    • On the other hand, World Health Organisation (WHO) had revised its air quality guidelines in 2021.
    • As a result, experts have been calling for revision of the standards.
• Lenient air quality standards of India —
  • • India’s own national air quality standards are much more lenient, even compared to WHO’s 2005 norms.
    • For example, the recommended PM2.5 concentration over a 24-hour period is 60 micrograms per cubic metre, compared to 25 micrograms advised by WHO’s 2005 guidelines.
    • Also, the annual national standard for PM10 and PM2. 5 is still 60 and40 micrograms per cubic metre, respectively.
    • On the other hand, WHO’s safe limit of 15 micrograms per cubic metre forPM10 and 5 micrograms per-cubic metre for PM2. 5 (as per 2021 guidelines).

About the ‘National Ambient Air Quality Standards’ –

• Ambient air quality refers to the condition or quality of air surrounding us in the outdoors.
• Under the authority of the Air (Prevention and Control of Pollution) Act of 1981, India’s Central Pollution Control Board sets national ambient air quality standards.
• The current National Ambient Air Quality Standards include following pollutants —
  • • Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Particulate Matter (size less than 10 µm), Particulate Matter (size less than 2.5 µm), Ozone (O3),
    • Lead (Pb), Carbon Monoxide (CO), Ammonia (NH3), Benzene (C6H6), Benzo(a)Pyrene (BaP)- particulate phase only, Arsenic (As), Nickel (Ni).

What are the WHO’s revised air quality guidelines of 2021?

• In September 2021, the World Health Organization (WHO) has strengthened its air quality guidelines.
• The revised norms recommend air quality levels for six pollutants —
  • • Ozone, nitrogen dioxide, sulphur dioxide and carbon monoxide.
    • The other two are PM10 and PM2.5 — particulate matter equal or smaller than 10 and 2.5 microns in diameter.
• The recommended levels for all the six pollutants have been revised downwards from the existing norms that have been in place since 2005.
• The WHO norms are not binding on any country.
• These are only recommended norms considered safe for human health, backed by scientific studies. However, air quality does affect the international image of a country.