In March 2025, IQAir, the technology partner of the UN, released the 2024 World Air Quality Report.
About this report
The
2024 World Air Quality Report evaluates the global state of air quality
for the year 2024. This comprehensive report presents PM2.5 air quality
data collected from 8,954 cities across 138 countries, regions, and
territories. The data used herein is sourced from over 40,000 regulatory
air quality monitoring stations and low-cost sensors, operated by a
diverse range of entities, including government agencies, research
institutions, non-profit organizations, schools, universities, private
sector companies, and dedicated citizen scientists worldwide.
The
PM2.5 data is measured in micrograms per cubic meter (μg/m³) and the
data is visualized as a function of the World Health Organization (WHO)
annual PM2.5 air quality guideline. The air quality metrics included in
this 2024 report derive from IQAir’s real-time online monitoring
platform, which systematically validates, calibrates, and harmonizes
data from air quality monitoring stations globally.
For further
historic air quality information categorized by city, country, and
region, the IQAir website offers an interactive map displaying annual
city concentrations alongside global rankings of air quality for the
8,954 cities featured in this report. IQAir is committed to engaging,
informing, and inspiring a collaborative effort among governments,
educators, researchers, non-profit organizations, businesses, and
citizens to elevate air quality awareness. Our goal is to facilitate
informed dialogue and promote actions that enhance air quality and
safeguard the health of communities and cities around the world.
Executive Summary
Air
pollution remains the greatest environmental threat to human health.
According to the World Health Organization (WHO), 99% of the global
population lives in areas that do not meet recommended air quality
guideline levels.1 Air pollution is the second leading global risk
factor for death, and the second leading risk factor for deaths among
children under five, following malnutrition, due to its significant
impact on respiratory and developmental health.2 In 2021 alone, 8.1
million total deaths were attributable to air pollution, with 58% of
those deaths caused by ambient PM2.5 air pollution.3
The United
Nations has declared access to healthy air is a universal human right.4
Exposure to PM2.5 contributes to and exacerbates various health
conditions, including asthma, cancer, stroke, and lung diseases.5 In
addition, exposure to elevated levels of fine particles during pregnancy
and early childhood are associated with congenital heart defects,
eczema and allergic disease, cognitive impairments and delays,
neurodevelopmental disorders, and mental health disorders.6
The
data used to create this report was compiled from over 40,000 air
quality monitoring stations and low-cost sensors worldwide, operated by
research institutions, government agencies, schools, universities,
non-profit organizations, private companies, and citizen scientists.
The
2023 World Air Quality Report included data from 7,812 locations in 134
countries, regions, and territories. In 2024, those numbers have grown
to 8,954 cities in 138 countries, regions, and territories. Coverage has
expanded in Africa to include Chad, the most polluted country in 2024,
along with Djibouti and Mozambique. The countries of Iran, Afghanistan,
and Burkina Faso (ranked 5th most polluted country in 2023) are notably
absent in 2024 due to a lack of data availability.
Only 12
countries, regions, and territories recorded PM2.5 concentrations below
the WHO annual PM2.5 guideline of 5.0 μg/m³, most of which were in the
Latin America and Caribbean or Oceania region; however in 2024, 17% of
cities included in the report met the WHO annual PM2.5 guideline level,
up from 9% in 2023. While this marks some progress, much more work has
yet to be done to protect human health, especially that of children. It
is our shared responsibility to safeguard the health and well-being of
the world’s children, who will one day become the leaders of tomorrow.
By equipping them with the knowledge and resources they need, we empower
them to tackle the global challenges of the future.