The new WHO air quality guidelines

In September 2021, the WHO released its updated air quality guidelines (AQG), marking the first time that they have provided new guidelines since 2005. As of 2019, 99% of the world was living under air quality conditions that did not meet these guidelines, leading to 6.7 million premature deaths annual on a global scale (a figure that represents the combined effects of outdoor and indoor air pollution)1. Read below to learn about the WHO’s updated AQG and what this means for your breathing health.

A photo of the WHO app on a smartphone

What are the WHO AQG?

Air pollution is a global health crisis affecting 99% of the world’s population. This means that nearly every single one of us, whether we reside in high-, medium-, or low-income countries, are breathing air that is not meeting the guidelines set by the WHO. These guidelines exist to support governments at all levels to implement actions that will protect their citizens from the dangers of air pollution. While there are always steps that we can take on the individual scale to reduce emissions that pollute our air, unfortunately, outdoor air pollution is usually out of the hands of the individual and needs to be addressed at local, national, and/or regional levels.

How are the AQG developed?

The recommendations are made based on extensive literature reviews and evaluation methods from experts and end-users from every corner of the globe. Using evidence-based data, the guidelines aim to limit values for certain air pollutants in the hopes of protecting public health. The process of generating each new set of guidelines involves the WHO creates multiple expert groups, each of which focuses on a specific function: some decide which pollutants pose the most risk, others draft up background material such as literature reviews, and the main expert group reviews the material and makes comments and adjustments2.

The first set of AQG was released in 1987, and several updates have been released since then. The goal is to publish regularly in order to ensure relevance and updated information based on studies published between guideline updates. Prior to the new set of guidelines in 2021, the last time that guidelines were released was in 2005.

The WHO has established AQG because it believes that breathing clean air is a human right.

A smokestack with polluted air billowing out

Targeted air pollutants

The air pollutants that pose the most risk to public health and are thus targeted by the WHO’s AQG are as follows:

  • Particulate matter (PM)
    • Studies have shown strong negative health effects as a result of exposure to this pollutant
    • Consists of sulphates, nitrates, sodium chloride, mineral dust, black carbon, and ammonia
  • Carbon monoxide (CO)
    • Colourless, odourless, tasteless, and very toxic
    • Caused by incomplete combustion of carbonaceous fuels (wood, petrol, charcoal, natural gas, and kerosene)
  • Ozone (O3)
    • One of the major components of photochemical smog
    • Forms when chemical pollution reacts with sunlight
  • Nitrogen dioxide (NO2)
    • A gas that is released mainly from the combustion of fuel in the transportation and industrial sector
  • Sulphur dioxide (SO2)
    • A colourless gas with a strong odour
    • Produced from the burning of fossil fuels and smelting of mineral ores1

2021 WHO AQG

The following chart compares the WHO’s AQG of 2021 versus the levels set in 2005:A list comparing the 2005 and 2021 WHO air quality limitsThese numbers represent target levels for the most common air pollutants.

What do these guidelines hope to achieve?

By providing limits on each pollutant based on scientific evidence from around the world, governments can then implement legislation to act and reduce the impacts of air pollution on their populations. These limits also provide knowledge about the hazardous properties of each of these pollutants and their impacts on human, animal, and environmental health.

Protect your lungs with an Eoleaf air purifier

As mentioned above, even with individuals having the best intentions doing their part to reduce their contributions to air pollution, air quality is often out of our hands. This means that we need to do all we can to protect our lungs and health at home and in the workplace. There are two ways to do this: the first is to properly ventilate your space by opening windows and doors regularly. This may not be an option for you due to high levels of outdoor pollution, uncomfortable or extreme outdoor temperatures, security concerns, and/or outdoor noise, amongst other concerns. The second way to protect yourself is, then, to equip your space with an air purifier.

Eoleaf offers medical-grade air purifiers with the most advanced technologies on the air purification market. All of our filters are layered, containing 9 different filtration technologies, including a HEPA (high efficiency purified air)-certified filter, an activated carbon filter, and UV sterilisation. The photo below shows our filter in more detail.

A diagram of our 9 filtration technologies

These filtration technologies are capable of removing all of the above-mentioned pollutants that are known to cause negative health effects. Start protecting your lungs today from dangerous air pollutants with an Eoleaf air purifier.


1 World Health Organization. (2022, December 19). Ambient (outdoor) Air Pollution. World Health Organization. Retrieved February 8, 2023, from

2 World Health Organization. (2021, September 22). What are the WHO air quality guidelines? World Health Organization. Retrieved February 8, 2023, from 

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