Global Air Quality Guidelines: WHO


    In News 

    • Recently, the World Health Organisation (WHO) released a revised Global Air Quality Guidelines announcing more stringent limits for six pollutant categories —particulate matter (PM), ozone (O3), nitrogen dioxide (NO2) sulfur dioxide (SO2) and carbon monoxide (CO). 

    Objective and Need 

    • Air pollution is one of the biggest environmental threats to human health, alongside climate change. 
      • Improving air quality can enhance climate change mitigation efforts while reducing emissions will, in turn, improve air quality.
      • The WHO move sets the stage for eventual shifts in policy in the government towards evolving newer stricter standards.
        • It will help Countries in protecting health as well as mitigating global climate change.

    Key features of WHO guidelines

    • The guidelines recommend new air quality levels to protect the health of populations, by reducing levels of key air pollutants, some of which also contribute to climate change. 
    • These guidelines are not legally binding.

    •  PM2.5: The upper limit of annual PM2.5 as per the 2005 standards is 10 micrograms per cubic metre. It has now been revised to 5 micrograms per cubic metre.
    • The 24-hour ceiling used to be 25 micrograms but has now dropped to 15. 
    • PM10:The PM10, or particulate matter of size exceeding 10 micrograms, the upper limit is 20 micrograms and has now been revised to 15 whereas the 24-hour value has been revised from 50 to 45 micrograms.


    • These new guidelines will have major implications for public health. 
      • They provide a practical tool for improving air quality around the world and a robust evidence-based for developing national and local air quality standards.
      • It guides legislation and policies, in order to reduce levels of air pollutants and decrease the burden of disease that results from exposure to air pollution across the world.
    • On India 
      • The move doesn’t immediately impact India as the National Ambient Air Quality Standards (NAAQS) don’t 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 don’t meet the NAAQS when calculated from 2011-2015.
    • Standards for a host of chemical pollutants
      • India’s NAAQs — last revised in 2009 — specify an annual limit of 60 micrograms per cubic metre for PM 10 and 100 for a 24-hour period. 
      • Similarly, it’s 40 for PM 2.5 annually and 60 for a 24-hour period. There are also standards for a host of chemical pollutants including sulphur dioxide, lead and nitrogen dioxide.

    What is Air pollution?

    • Air pollution refers to the release of pollutants into the air that is detrimental to human health and the planet as a whole.
    • Source of Air Pollution
      • Nitrogen dioxide: It is one of the major pollutants and major sources of NOx include emissions from motor vehicle exhaust, industrial facilities, and chemical solvents.
      • Agriculture & Allied Sources: Ammonia (NH3) -It is another gaseous pollutant that is monitored.
        • It occurs naturally in air, soil and water, and is used as an agricultural fertiliser and in cleaning products.
        • Short-term inhalation of high levels of ammonia can cause irritation and serious burns in the mouth, lungs and eyes.
    • Stubble burning: It is also one of the major sources of air pollution in northern India, especially in winters.
    • Sulphur dioxide (SO2): They emitted from the combustion of fossil fuels have, historically, been the main component of air pollution in many parts of the world.
      • The largest source of SO2 in the atmosphere is burning fossil fuels by power plants and other industrial facilities.
      • Short-term exposure to SO2 can harm the respiratory system, making breathing more difficult.
    • Particulate Matter:  Particulate matter (PM) are inhalable and respirable particles composed of sulphate, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water.
      • Both PM2.5 and PM10 are capable of penetrating deep into the lungs but PM2.5 can even enter the bloodstream, primarily resulting in cardiovascular and respiratory impacts, and also affecting other organs. 
      • In 2013, outdoor air pollution and particulate matter were classified as carcinogenic by WHO’s International Agency for Research on Cancer (IARC).
    • Carbon monoxide (CO): It is a toxic, colourless and odourless gas, given off when fuel containing carbon, such as wood, coal and petrol, are burned.
      • Major sources of methane include waste and fossil fuel and agricultural industry.
    • Ozone (O3): It occurs both in the Earth’s upper atmosphere and at ground level. At the ground, O3 is created by the chemical reaction between oxides of nitrogen (NOx) and volatile organic compounds.
      • It is formed when pollutants emitted by cars, power plants, refineries and other sources chemically react in presence of sunlight.
      • It can trigger a variety of health problems, including chest pain, throat irritation and airway inflammation.

     Associated risks 

    • Air pollution is a threat to health in all countries, but it hits people in low- and middle-income countries the hardest. 
    • Every year, exposure to air pollution is estimated to cause 7 million premature deaths and result in the loss of millions more healthy years of life. 
    • In children, this could include reduced lung growth and function, respiratory infections and aggravated asthma. 
    • In adults, ischaemic heart disease and stroke are the most common causes of premature death attributable to outdoor air pollution, and evidence is also emerging of other effects such as diabetes and neurodegenerative conditions.
    • This puts the burden of disease attributable to air pollution on a par with other major global health risks such as unhealthy diet and tobacco smoking.
    • There is a body of scientific evidence to prove that air pollution is leading to severe health impacts and 90% of the entire global population is breathing polluted air.

    Solutions Provided by WHO 

                                         Image Courtesy: WHO

    Steps Taken by Government

    • The Pradhan Mantri Ujjwala Yojana Household LPG program and other schemes have helped to dramatically expand access to clean energy, especially for rural households.
    • National Clean Air Programme (NCAP)
      • It was launched in 2019)now renamed National Clear Air Mission which aims to reduce the particulate matter (PM10 and PM2.5) concentrations in the air by 20–30% by 2024.
    • Commission for Air Quality Management
      • The Commission for Air Quality Management in the National Capital Region and adjoining areas, 2020 — with a provision for a fine of Rs 1 crore and/or jail for 5 years for those violating air pollution norms.

    Source: TH