GS3 PYQ (Mains Answer Writing): Global Air Quality Guidelines (AQGs) | Environment for UPSC CSE PDF Download

Describe the key points of the revised Global Air Quality Guidelines (AQGs) recently released by the World Health Organisation (WHO). How are these different from its last update in 2005? What changes in India’s National Clean Air Programme are required to achieve these revised standards?  (UPSC MAINS GS3 )

The WHO recently released an updated version of the Global Air Quality Guidelines (AQGs). The guidelines recommend new air quality levels to protect the health of populations, by reducing levels of key air pollutants.
Key Points:

• WHO’s new guidelines recommend air quality levels for six pollutants — particulate matter (PM 2.5 & PM10), ozone (O₃), nitrogen dioxide (NO₂) sulfur dioxide (SO₂) and carbon monoxide (CO).
• The annual average for PM2.5 should not exceed 5 micrograms per cubic metre of air, while the 24-hour average should not exceed 15 micrograms per cubic metre.
• The annual average for PM 10 should not exceed 15 micrograms per cubic metre of air, while the 24-hour average should not exceed 45 micrograms per cubic metre.
• The ozone levels average should not exceed 100 micrograms per cubic metre over a 24-hour period.
• The nitrogen oxide levels should not exceed 25 micrograms per cubic metre over a 24-hour period.
• The sulphur dioxide levels should not exceed 40 micrograms per cubic metre  over a 24-hour period.
• The carbon monoxide levels should not exceed 4 micrograms per cubic metre  over a 24-hour period.

Global Air Quality Guidelines 2021 vs Global Air Quality Guidelines 2021
The centre has launched National Clean Air Programme (NCAP) to tackle air pollution in 122 cities by aiming for a 20-30 percent reduction in PM10 and PM2.5 concentrations by 2024, compared to 2017.
Changes required in India’s NCAP

• India’s air pollution standards are more relaxed in comparison to WHO’s prescribed guidelines. Thus, efforts are needed to make the guidelines more stringent with revised targets. 
• Under the proposed new Mission – Clean Air for All, government tends to make targets of PM2.5 & PM10 more stringent. 
• There is a need to adopt an airshed approach to take measures to deal with air pollution. Under this approach, the policymakers will have to plan actions keeping in view geographical, meteorological and other common factors which pollute air within the airshed.

Topics Covered - Global Air Quality Guidelines