Since WHO’s last 2005 global update, there has been a marked increase of evidence that shows how air pollution affects different aspects of health. For that reason, and after a systematic review of the accumulated evidence, WHO has adjusted almost all the AQGs levels downwards, warning that exceeding the new air quality guideline levels is associated with significant risks to health. At the same time, however, adhering to them could save millions of lives.
World Health Organization (WHO) Global Air Quality Guidelines (AQGs)
provide clear evidence of the damage air pollution inflicts on human
health, at even lower concentrations than previously understood.
guidelines released on Wednesday 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.
Since WHO’s last 2005
global update, there has been a marked increase of evidence that shows
how air pollution affects different aspects of health. For that reason,
and after a systematic review of the accumulated evidence, WHO has
adjusted almost all the AQGs levels downwards, warning that exceeding
the new air quality guideline levels is associated with significant
risks to health. At the same time, however, adhering to them could save
millions of lives.
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
In adults, ischemic heart disease and stroke are the most
common causes of premature death attributable to outdoor air pollution and evidence, the WHO says in a statement is also emerging of other effects such as diabetes and
neurodegenerative conditions like memory disorders.
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.
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), it also has an impact on
other damaging pollutants.
The health risks associated with particulate matter equal or smaller than 10 and 2.5 microns (µm) in diameter (PM₁₀ and PM₂.₅, respectively) are of particular public health relevance. 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.
primarily generated by fuel combustion in different sectors, including
transport, energy, households, industry, and from agriculture. In 2013,
outdoor air pollution and particulate matter were classified as
carcinogenic by WHO’s International Agency for Research on Cancer
The guidelines also highlight good practices for the
management of certain types of particulate matter (for example, black
carbon/elemental carbon, ultrafine particles, particles originating from
sand and dust storms) for which there is currently insufficient
quantitative evidence to set air quality guideline levels.
applicable to both outdoor and indoor environments globally, and cover
“Air pollution is a threat to health in all
countries, but it hits people in low and middle-income countries the
hardest,” said WHO Director-General, Dr Tedros Adhanom Ghebreyesus.
“WHO’s new Air Quality Guidelines are an evidence-based and practical
tool for improving the quality of the air on which all life depends. I
urge all countries and all those fighting to protect our environment to
put them to use to reduce suffering and save lives.”
in air pollution exposure are increasing worldwide, particularly as
low- and middle-income countries are experiencing growing levels of air
pollution because of large-scale urbanization and economic development
that has largely relied on the burning of fossil fuels.
WHO estimates that millions of deaths are caused by the effects of air
pollution, mainly from noncommunicable diseases. Clean air should be a
fundamental human right and a necessary condition for healthy and
productive societies. However, despite some improvements in air quality
over the past three decades, millions of people continue to die
prematurely, often affecting the most vulnerable and marginalized
populations,” said WHO Regional Director for Europe, Dr Hans Henri P.
“We know the magnitude of the problem and we know how to solve
it. These updated guidelines give policy-makers solid evidence and the
necessary tool to tackle this long-term health burden.”
assessments of ambient air pollution alone suggest hundreds of millions
of healthy life years of life lost, with the greatest attributable
disease burden seen in low and middle-income countries.
The more exposed
to air pollution they are, the greater the health impact, particularly
on individuals with chronic conditions (such as asthma, chronic
obstructive pulmonary disease, and heart disease), as well as older
people, children and pregnant women.
In 2019, more than 90%
of the global population lived in areas where concentrations exceeded
the 2005 WHO air quality guideline for long term exposure to PM₂.₅.
Countries with strong policy-driven improvements in air quality have
often seen marked reduction in air pollution, whereas declines over the
past 30 years were less noticeable in regions with already good air
goal of the guideline is for all countries to achieve recommended air
Conscious that this will be a difficult task for many
countries and regions struggling with high air pollution levels, WHO has
proposed interim targets to facilitate stepwise improvement in air
quality and thus gradual, but meaningful, health benefits for the