Almost everyone breathes air that is dirtier than WHO's guideline, and outdoor and household air pollution together are among the largest causes of early death worldwide.
Updated October 13, 2026. Written from the sources listed below, not independently peer-reviewed.
Out of every 100 people on Earth, how many live where outdoor fine-particle pollution is above WHO's annual guideline?
7.9 million
Deaths linked to air pollution
About one in eight deaths worldwide. Of these, 4.9 million are attributed to outdoor PM2.5, 2.8 million to household air pollution and 470,000 to ozone (modelled estimates that overlap).
Data year 2023. Source: Health Effects Institute, 2025
More than 99%
People living above WHO's PM2.5 guideline
Fewer than 1% live where the annual guideline of 5 µg/m³ is met. 36% (2.8 billion people) live above even the least strict interim target of 35 µg/m³.
Data year 2023. Source: Health Effects Institute, 2025
About 2 billion
People cooking mainly with polluting fuels
1.5 billion of them live in rural areas, and around 970 million live in sub-Saharan Africa.
Data year 2024. Source: World Health Organization, 2026
Unit: % of population
WHO estimates for SDG indicator 7.1.2 as published in the World Bank's World Development Indicators, rounded to whole numbers. The share rose by about 1.5 percentage points a year in 2010–2020 but only about 1 point a year since 2020. Gains were largest in South Asia (31% to 74% from 2010 to 2024).
SDG target 3.9 calls for a substantial cut in deaths and illness from air pollution by 2030, and SDG target 7.1 for universal access to modern energy, including clean cooking (indicator 7.1.2), by the same year. WHO's 2026 update of the SDG data finds that global PM2.5 levels fell until 2020 and have stayed largely unchanged since. About 2 billion people still cooked mainly with polluting fuels in 2024, and the number without clean cooking in sub-Saharan Africa, around 970 million, may reach 1 billion by 2027. WHO now also works towards a 50% cut in deaths related to air pollution by 2040.
Low- and middle-income countries accounted for 90% of all deaths linked to air pollution in 2023. India and China each had more than 2 million such deaths.
Source: Health Effects Institute, 2025South Asia had the highest age-standardised death rate from air pollution in 2023, 191 per 100,000 people, more than eleven times the rate in high-income countries (16.7).
Source: Health Effects Institute, 2025Clean cooking has spread unevenly: from 2010 to 2024 the share of people cooking mainly with clean fuels rose from 31% to 74% in South Asia, but only from 12% to 23% in sub-Saharan Africa.
Source: World Bank, World Development Indicators, 2026Women and children, who usually do household chores and spend the most time near the hearth, carry the heaviest burden of household smoke. It caused more than 309,000 deaths of children under five in 2021.
Source: World Health Organization, 2025Instead of one “percent solved” score, DO GOOD rates three separate dimensions. A problem can have mature solutions that still reach too few people. These ratings are an editorial reading of the sources on this page, not a measured index.
Has the situation improved in the real world?
ModerateThe age-standardised death rate from air pollution fell by 21% between 2013 and 2023, mainly because fewer people are exposed to household smoke. Over the same period, death rates linked to outdoor PM2.5 and ozone rose, and ozone deaths grew from 261,000 in 2000 to 470,000 in 2023.
How mature and validated are the available solutions?
ModerateEmission controls for power plants, industry and vehicles are well established and have cut outdoor pollution quickly where enforced, as in China after 2013. Clean stoves and fuels work technically, but the large HAPIN trial found that switching to gas did not significantly reduce severe pneumonia in infants, so the health gain from partial exposure cuts is less certain than once assumed.
How widely are effective solutions actually used?
ModerateClean cooking and emission controls have spread widely, yet in 2023 almost 2.6 billion people were still exposed to smoke from solid cooking fuels, fewer than 1% of people lived where WHO's annual PM2.5 guideline is met, and 36% lived above even the least strict interim target.
Exposure is estimated by combining ground monitors, satellite data and atmospheric models, and every death estimate carries a wide uncertainty range (outdoor PM2.5 deaths in 2023: 3.9 to 6.1 million). Ground data are sparse in many lower-income regions where burdens are high, and the evidence linking PM2.5 to dementia is less precise.
Household air pollution is declining, driven by fast gains in Asia, but the number of people without clean cooking is growing in sub-Saharan Africa. Global PM2.5 levels have been roughly flat since 2020 and ozone exposure keeps rising.
Air pollution damages health in two settings. Outdoors, fine particles known as PM2.5, which come from vehicles, coal-fired power plants, industry, household fuel use, waste burning and dust, reach deep into the lungs and bloodstream, and ground-level ozone forms from gases released mainly by burning fossil fuels. Indoors, about 2 billion people still cook mainly over open fires or with inefficient stoves that burn wood, dung, crop waste, coal or kerosene. The State of Global Air report estimates that air pollution contributed to 7.9 million deaths in 2023, about one in eight deaths worldwide, making it the second leading risk factor for early death after high blood pressure.
Most of these deaths come from noncommunicable diseases such as heart disease, stroke, chronic lung disease, lung cancer, diabetes and dementia, while in young children lung infections such as pneumonia are a major cause. The burden falls overwhelmingly on low- and middle-income countries, with the highest death rates in South Asia, sub-Saharan Africa, and North Africa and the Middle East, and household smoke hits women and children hardest because they spend the most time near the fire. Global PM2.5 levels fell until 2020 but have barely changed since, ozone exposure keeps rising, and in sub-Saharan Africa the number of people without clean cooking is still growing.
There is no single number for air pollution. Agencies track pollutant levels outdoors, how households cook, and modelled deaths. The main measures are:
Outdoor fine particles (PM2.5)
The yearly average concentration of particles smaller than 2.5 micrometres, usually weighted by where people live. WHO's 2021 guideline is 5 µg/m³, with less strict interim targets up to 35 µg/m³ for highly polluted places. SDG indicator 11.6.2 tracks annual PM2.5 levels in cities.
Ozone
A gas formed near the ground from emissions of vehicles, power plants and other sources. It harms the lungs and is also a greenhouse gas. It is monitored on the ground far less routinely than particles.
Household air pollution
Usually measured indirectly through SDG indicator 7.1.2, the share of people who rely mainly on clean fuels and technologies for cooking: electricity, gas (LPG, natural gas, biogas), solar, alcohol fuels, and biomass stoves that meet WHO emission targets. Other estimates count people exposed to smoke from solid fuels instead (almost 2.6 billion in 2023), which is why totals differ.
Attributable deaths
Modelled estimates that combine exposure, population and disease data with risk curves from health studies; SDG indicator 3.9.1 tracks the death rate from ambient and household air pollution. Results depend on the model: WHO puts combined deaths at 6.7 million a year, HEI and IHME at 7.9 million for 2023. Estimates for single pollutants overlap and cannot simply be added.
What works
Binding limits for power plants, industry and vehicles, backed by enforcement, can lower pollution within a few years. Under China's 2013–2017 action plan, national population-weighted PM2.5 fell from 61.8 to 42.0 µg/m³. A modelling study attributed the fall mainly to emission cuts rather than weather, led by stricter industrial standards, boiler upgrades, closing outdated plants and cleaner household fuels, and estimated that these measures avoided about 370,000 deaths.
Limits
Even after this progress, China's average in 2017 was more than eight times WHO's guideline. Such plans need strong regulators, reliable monitoring and sustained funding.
What works
Replacing open fires and simple stoves with electricity, LPG, biogas, ethanol or certified low-emission stoves cuts household smoke. The share of the world population cooking mainly with clean fuels rose from 57% in 2010 to 75% in 2024, helped by large national programmes such as India's Ujjwala scheme for LPG and China's rural clean heating programme.
Limits
Fuel refills and appliances cost money that the poorest households often lack, and many families keep using the old stove alongside the new one. In the HAPIN trial, children's exposure fell sharply with gas cooking but remained well above the level of WHO's annual guideline, and severe infant pneumonia did not fall significantly.
What works
Shifting electricity from coal to renewable and low-emission sources, tightening vehicle and fuel standards, and investing in public transport, walking and cycling reduce both particles and the gases that form ozone and particles in the air.
Limits
These are long-term infrastructure changes. Cities in low-income countries often lack the funds, and older vehicles and generators remain in use for many years.
What works
Collecting and recycling municipal waste and giving farmers alternatives to burning stubble removes large seasonal and local sources of smoke.
Limits
Alternatives must be cheaper or more convenient than burning, or bans are widely ignored. Smoke from farm fires often drifts into other districts or states, so action depends on cooperation across borders.
What works
WHO's 2021 guidelines, with an annual PM2.5 guideline of 5 µg/m³, give governments an evidence-based reference for setting legal standards and step-by-step interim targets. Public monitoring data let authorities track progress and warn people on bad days.
Limits
The guidelines are not legally binding, and many national standards are far weaker. Without reliable monitoring, standards cannot be enforced or checked.
Promising, but not proven at scale. The stage shows how far each approach has come; it is not a recommendation.
Small, inexpensive sensors can add measurements in neighbourhoods, schools and countries that have few reference monitors. A WMO review found that their accuracy varies widely between devices and that they drift and react to humidity unless carefully calibrated, so they can complement but not replace reference instruments.
Combining satellite observations with ground monitors and atmospheric models now gives PM2.5 estimates for places where no monitors exist or data are not public. These estimates underpin global burden figures, but they are only as reliable as the ground data used to check them.
Efficient electric appliances such as pressure cookers and induction stoves produce no smoke in the home. They are promising where the grid or mini-grids are reliable, but upfront cost, power supply and cooking habits limit uptake, and evidence on sustained use at scale is still building.
WHO tools such as AirQ+ for outdoor pollution and BAR-HAP for household energy help governments estimate the health effects and costs of different clean-air options. Their usefulness depends on local data, which are often thin where pollution is worst.
Implementation gap
While access has almost doubled in most of Asia since 2010, around 970 million people in sub-Saharan Africa lack clean cooking and the number may reach 1 billion by 2027, as population growth outpaces new connections.
Implementation gap
Giving a household a clean stove is not enough. Refills, electricity tariffs and replacement parts must remain affordable year after year, or families return to free or cheap wood, dung and charcoal.
Coordination gap
Pollution comes from vehicles, household fuels, power plants, industry, farming, waste, dust and wildfires, and it crosses city and national borders. Cutting it requires energy, transport, agriculture, environment and health authorities to act together, which rarely happens.
Knowledge gap
Ground monitors are scarce in many lower-income regions where the burden is highest, and ozone is monitored far less routinely than particles. Global estimates therefore lean heavily on models and satellites.
Knowledge gap
In the HAPIN trial in India, Guatemala, Peru and Rwanda, gas cooking cut children's median PM2.5 exposure from 66.0 to 24.2 µg/m³, yet severe infant pneumonia did not differ significantly (5.67 versus 6.06 cases per 100 child-years). It is unclear how far exposure must fall before the expected health benefits appear.
Technology gap
Reference-grade monitors are expensive to buy and run, and cheaper sensors still need careful calibration to give trustworthy data. Better low-cost instruments would make monitoring possible in far more places.
Unresolved questions, not vetted breakthroughs. Answering any of them would change what is possible.
Large reductions in household smoke have not always produced measurable health gains. How low must exposure fall, from all sources including neighbours and outdoor air, before pneumonia, low birth weight and heart and lung disease decline?
PM2.5 is a mix from many sources. Are particles from coal, traffic, biomass smoke, dust or wildfires equally harmful, and should policies target the most toxic sources first?
Studies link long-term PM2.5 exposure to dementia, but the evidence is less precise than for heart and lung disease. Is the link causal, and how large is it?
Which combinations of policies cut pollution most cost-effectively in rapidly growing cities in Africa and South Asia, where monitoring is sparse and many sources are informal?
Follow official air quality forecasts where you live. On high-pollution days, people with heart or lung conditions, older adults, pregnant women and young children benefit most from limiting time and exercise outdoors.
Avoid burning garden waste or rubbish, limit wood burning at home, and walk, cycle or use public transport for short trips where you can. These choices reduce pollution on your own street.
Before you give, look for organisations that report not only how many stoves or connections they provide, but whether households keep using them and whether exposure actually falls.
Local decisions on traffic, heating, waste and industrial permits shape the air you breathe. Taking part in consultations and telling elected representatives that you support stronger standards can influence them.
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Health Effects Institute (HEI) and Institute for Health Metrics and Evaluation (IHME), published 2025
Global and regional estimates for 2023 based on the Global Burden of Disease study, released 22 October 2025. Source of the 7.9 million deaths and their split by pollutant, the ranking as second risk factor, exposure above WHO's guideline and interim target, the 2.6 billion people exposed to solid-fuel smoke, death rates by region, the 21% fall in the age-standardised death rate, ozone and dementia figures, and methods and data gaps.
World Health Organization (news release, 29 June 2026), published 2026
WHO's summary of updated data for SDG indicators 3.9.1, 7.1.2 and 11.6.2. Source of the PM2.5 plateau since 2020, the 2 billion people cooking with polluting fuels in 2024, the rural and sub-Saharan Africa figures, regional trends, WHO decision-support tools and the 2040 mortality target.
World Health Organization (16 December 2025), published 2025
Source of the definition of clean fuels and technologies, the 309,000 deaths of children under five in 2021, the 44% share of under-five pneumonia deaths, the burden on women and children, time lost to fuel collection, and WHO's combined estimate of 6.7 million premature deaths a year.
World Bank, World Development Indicators (data from WHO / Tracking SDG 7), published 2026
Official SDG 7.1.2 series compiled by WHO, last updated 8 October 2026. Source of the global trend (57% in 2010, 64% in 2015, 71% in 2020, 75% in 2024) and of the values for South Asia and sub-Saharan Africa.
Zhang Q. et al., Proceedings of the National Academy of Sciences 116(49): 24463–24469, published 2019
Peer-reviewed modelling study of China's Air Pollution Prevention and Control Action Plan. Source of the fall in population-weighted PM2.5 from 61.8 to 42.0 µg/m³, the measures that drove it and the estimated 370,000 avoided deaths.
McCollum E.D. et al., New England Journal of Medicine 390(1): 32–43, published 2024
Randomised trial of 3,200 pregnant women in India, Guatemala, Peru and Rwanda (DOI 10.1056/NEJMoa2305681; abstract on a co-investigator institution's research portal). Source of the exposure reduction (24.2 versus 66.0 µg/m³) and the lack of a significant effect on severe infant pneumonia.