New Evidence Led To WHO’s New Air Quality Standard

What is the news?

The World Health Organization(WHO) released the Global Air Quality Guidelines(AQGs) recently.

Why was a higher standard necessary?

Since the last global update in 2005, there has been a marked increase in quality and quantity of evidence that shows how air pollution affects different aspects of human health.

The evidence also shows that adhering to new levels could save millions of lives. It shows around 80% of deaths globally attributed to PM2.5 exposure could be avoided if countries attain the annual AQG (air quality guidelines) level.

Even the attainment of an interim target for PM2.5 (the 2005 level) would result in a nearly 48% decrease in total deaths.

So, the clear evidence of health benefits prompted the global health body to update its guidelines on air quality standards.

Note: The Particulate Matter (PM), primarily generated by fossil fuel combustion, is even classified as carcinogenic by the WHO’s International Agency for Research on Cancer (IARC).

Where does India stand?

India always has less stringent benchmarks for almost all key pollutants compared to the ones set by the WHO.

The 2021 AQG has made India’s national ambient air quality standards (NAAQS), set in 2009, look more relaxed. Most Indian cities had, in fact, failed to meet even the WHO 2005 AQG level.

Under 2021 AQG,

– new annual standard for PM2.5 is set at 5 micrograms per cubic meter (μg/m³ ) compared to 10 μg/m³ in 2005 whereas its 24-hour mean is now fixed at 15 μg/m³ compared to 25 μg/m³ in 2005.

– On the other hand, the acceptable level for PM2.5 in India is much higher – 40 μg/m³ and 60 μg/m³ for annual and 24-hour mean, respectively.

– Similarly, India’s annual acceptable level for PM10 is 60 μg/m³ which is four times higher than the new WHO standards.

Will India revise its NAAQS, taking into account the WHO 2021 AQG?

India has already started working on revising its air quality standards. Though the country is expected to make its NAAQS more stringent compared to its 2009 standards, it won’t be as stringent as the WHO 2021 AQG.

Experts will factor in local meteorological and topographical conditions for arriving at new NAAQS next year. Besides the six classical pollutants, India’s NAAQS basket has two more pollutants – benzene and ammonia.

What’s the global context of the new WHO standards?

Release of new air quality standards at this juncture is significant, especially when there has been a growing momentum to bring more and more countries on board to get pledges for deep emission cuts ahead of 26th session of the UN climate conference (COP26).

Since some air pollutants – particularly black carbon (a component of PM) and tropospheric (ground-level) ozone – are also shortlived climate pollutants, efforts to improve air quality by reducing or phasing out fossil fuel can enhance climate change mitigation.

Source: This post is based on the article “New Evidence Led To WHO’s New Air Quality Standard” published in TOI on 27th Sep 2021.