WHO global air quality norms

Subject – Environment

Context – WHO raises the bar on clean air

Concept –

The World Health Organization (WHO) has raised the bar further to safeguard public health even before the global community could comply with the current benchmarks for clean air.
The WHO’s new air quality guidelines — Global Air Quality Guidelines (AQGs) — released September 22, 2021, has redefined the threshold of safe air.
This is the first revision after the last updation in 2005 — about 15 years ago. Currently, 90 per cent of the global population and nearly everyone in India are breathing air that defies the current guidelines of the WHO.
The primary focus is on significant tightening of the guidelines for particulate matter, which is responsible for the highest number of air pollution related deaths worldwide — nearly seven million. The guidelines for key gases have also been revised.

WHO’s new guidelines recommend air quality levels for 6 pollutants, where evidence has advanced the most on health effects from exposure. When action is taken on these so-called classical pollutants – particulate matter (PM), ozone (O3), nitrogen dioxide (NO2) sulfur dioxide (SO2) and carbon monoxide (CO), also has an impact on other damaging pollutants.
It is, however, not clear why the annual standard for sulphur dioxide (SO2) is missing and the 24-hour guideline has been made more lax at 40 μg / m3, from 20 μg / m3 — two times more lenient.
- This cannot be explained as SO2 is directly linked with the use of sulphur-rich fuels that includes coal and other dirtier industrial fuels that are widely used across the developing world. Moreover, SO2 also contributes to the formation of secondary particulate or sulphates.
This time, the WHO has also included other fractions of particulate matter (ie black carbon / elemental carbon, ultrafine particles and particles originating from sand and dust storms).
- Numerical AQG levels could not be established for them and therefore, a best practice approach is required for mitigation.
But the latest State of Global Air Report 2020 has stated that there has been little or no progress in improving air quality in many parts of the world during 2019. Dangerous levels persist in low- and middle-income countries.

Impact on India –

The move does not have an immediate effect in India as the National Ambient Air Quality Standards (NAAQS) do not meet the WHO’s existing standards.
The government has a dedicated National Clean Air Programme that aims for a 20% to 30% reduction in particulate matter concentrations by 2024 in 122 cities, keeping 2017 as the base year for the comparison of concentration. These are cities that do not meet the NAAQS when calculated from 2011 to 2015.
India’s NAAQs — last revised in 2009 — specify an annual limit of 60 microgram per cubic metre for PM10 and 100 for a 24-hour period. Similarly it’s 40 for PM 2.5 annually and 60 on a 24-hour period.
There are also standards for a host of chemical pollutants including sulphur dioxide, lead and nitrogen dioxide.

National Ambient Air Quality Standards (NAAQS)

Air (Prevention and Control of Pollution) Act empowers Central Pollution Control Board (CPCB) to set standards for the quality of air.
Current NAAQS were notified by CPCB in the year 2009.
Pollutants covered under NAAQS are Sulphur Dioxide (SO₂), Nitrogen Dioxide (NO2), Particulate Matter (PM 10, PM 2.5), Ozone (O3), Lead (Pb), Carbon Monoxide (CO), Ammonia (NH3), Benzene (C6H6), Benzo(a)Pyrene (BaP), Arsenic(As), Nickel (Ni).

National Clean Air Programme

A long-term, time-bound, national level strategy to tackle the air pollution problem across the country in a comprehensive manner with targets to achieve 20% to 30% reduction in Particulate Matter concentrations by 2024 keeping 2017 as the base year for the comparison of concentration.
Under NCAP, 122 non-attainment cities have been identified across the country based on the Air Quality data from 2014-2018.
- Non-attainment cities: These are those that have fallen short of the National Ambient Air Quality Standards (NAAQS) for over five years.
The city specific action plans have been prepared which, inter-alia, include measures for strengthening the monitoring network, reducing vehicular/industrial emissions, increasing public awareness etc. Implementation of the city specific action plans are regularly monitored by Committees at Central and State level namely Steering Committee, Monitoring Committee and Implementation Committee.
Air quality of cities is monitored by State Pollution Control Boards which publishes their results from time to time. Some Smart Cities have established Integrated Command and Control Centres (ICCCs) which are also connected to Air Quality Monitors (AQMs) for effective monitoring.