How many people die from air pollution?

WHO estimates air pollution causes approximately 7 million premature deaths per year: 4.2 million from outdoor (ambient) air pollution and 3.2 million from household air pollution from cooking with solid fuels. This makes air pollution the largest single environmental health risk globally — exceeding the combined mortality from HIV/AIDS, tuberculosis and malaria.

What is PM2.5 and why is it dangerous?

PM2.5 refers to fine particulate matter with diameters of 2.5 micrometres or less. It penetrates deep into the lung's alveoli and crosses into the bloodstream — causing inflammation throughout the body. PM2.5 exposure is causally linked to ischaemic heart disease, stroke, lung cancer, COPD, lower respiratory infections and type 2 diabetes. There is no safe level of PM2.5 exposure — risk increases linearly from zero.

What are WHO's 2021 Air Quality Guidelines?

WHO's 2021 Air Quality Guidelines (AQG) — updated from 2005 — set the most stringent evidence-based air quality targets ever: annual mean PM2.5 of 5 μg/m³ (down from 10 in 2005); 24-hour PM2.5 of 15 μg/m³; annual PM10 of 15 μg/m³; 8-hour ozone of 60 μg/m³. The vast majority of cities globally — including in high-income countries — exceed these levels. Achieving them would prevent millions of deaths per year.

What causes outdoor air pollution?

Outdoor air pollution comes from: energy production (coal and gas power plants); industrial processes (metal smelting, cement, chemicals); road traffic (diesel and petrol engines); agriculture (ammonia from fertilisers, crop burning); waste burning; and natural sources (dust, wildfires, volcanic emissions). In most cities, road traffic and energy production are the dominant sources of PM2.5 and NOx.

What is household air pollution?

Household air pollution occurs when solid fuels (wood, charcoal, coal, dung, crop residues) or kerosene are burned in open fires or inefficient stoves for cooking and heating. Approximately 2.4 billion people cook this way. Indoor PM2.5 concentrations can exceed outdoor levels by 100-fold in poorly ventilated kitchens. Women who cook and children present during cooking have the highest exposures.

Which diseases does air pollution cause?

Air pollution causes and worsens: ischaemic heart disease and stroke (the largest categories — vascular disease from PM2.5 entering the bloodstream); COPD and lower respiratory infections (from chronic airway inflammation); lung cancer (PM2.5 is a Group 1 carcinogen); type 2 diabetes; and adverse pregnancy outcomes (preterm birth, low birth weight). Air pollution also worsens existing asthma and cardiovascular disease.

How does air pollution relate to climate change?

The same fossil fuel combustion that drives climate change also produces PM2.5, NOx, ozone and SOx that damage health. Wildfires — worsened by climate change — generate massive PM2.5 plumes. Climate change also worsens ozone formation and extends pollen seasons. Clean energy transitions — away from coal, oil and gas — simultaneously reduce GHG emissions and air pollution deaths, creating major health co-benefits that can accelerate climate policy.

What can individuals do about air pollution?

Individual actions with the largest impact: switch from wood/coal cooking to LPG, electric or improved stoves; use air purifiers with HEPA filters indoors; avoid high-traffic routes for walking/cycling (or use masks with PM2.5 filtration); check daily air quality index and avoid outdoor exercise on high-pollution days. However, individual action is insufficient — structural policies (vehicle emission standards, coal phase-out, industrial regulation, clean cooking subsidies) drive population-level change.

What does WHO recommend for clean cooking?

WHO's 2014 Indoor Air Quality Guidelines recommend clean cooking — defined as fuels and technologies that produce PM2.5 emissions below threshold levels. Liquefied petroleum gas (LPG), natural gas, electricity, ethanol and biogas are recommended. Improved biomass stoves with chimneys reduce PM2.5 but rarely reach clean levels. Transitioning 2.4 billion people from polluting to clean cooking is a major SDG 7 (clean energy) and SDG 3 (health) priority.

How is air quality measured?

Air quality is measured by continuous monitoring stations (reference standard) or low-cost sensors. The Air Quality Index (AQI) — used by most countries — combines readings from multiple pollutants (PM2.5, PM10, O3, NO2, SO2, CO) into a single number with colour-coded risk categories. WHO's Global Ambient Air Quality database tracks annual mean PM2.5 for 6,000+ cities globally.

What is Georgia's air quality situation?

Georgia faces significant air quality challenges, particularly in Tbilisi and the industrial Rustavi region — from vehicle emissions, coal burning for heating and industrial sources. Georgian Medical Journal and PHIG have engaged with air quality and respiratory health as public health priorities. Household air pollution from wood burning for heating is a concern in rural areas.

How does GMJ News cover air pollution?

GMJ News tracks WHO Air Quality Guideline updates, global burden of disease estimates, clean cooking initiatives, climate-health links and air quality policy. Air pollution is a direct public health priority for Georgia, given urban air quality challenges in Tbilisi and household burning in rural areas.

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Air Pollution

GMJ News knowledge hub · last reviewed September 2026 · Georgian Medical Journal

Summary Statistics Glossary GMJ news FAQ Documents Organizations Research

Air pollution is the world's largest single environmental health risk: 7 million premature deaths a year from outdoor (4.2M) and household (3.2M) air pollution — more than HIV/AIDS, tuberculosis and malaria combined (WHO). Shockingly, 99% of the world's population breathes air that exceeds WHO quality guideline levels, with the burden heaviest in South Asia, Sub-Saharan Africa and parts of Eastern Europe. The WHO 2021 Air Quality Guidelines are the global evidence standard; clean energy, clean transport and clean cooking fuels are the three systemic solutions.

Key messages

7 million deaths

Air pollution causes approximately 7 million premature deaths every year — 4.2 million from outdoor (ambient) air pollution and 3.2 million from household air pollution from cooking fires — more than HIV/AIDS, tuberculosis and malaria combined (WHO).

99% breathe polluted air

WHO estimates that 99% of the world's population lives in areas where air quality fails WHO guideline levels. The burden falls heaviest on South Asia, Sub-Saharan Africa and parts of Eastern Europe.

Disease driver

Air pollution causes stroke (28% of deaths), ischaemic heart disease (26%), COPD (22%), lower respiratory infections (21%) and lung cancer (14%). PM2.5 is the most important pollutant for health — penetrating the lung's gas exchange surface.

Household air pollution

Approximately 2.4 billion people cook with open fires or inefficient stoves burning biomass, coal or kerosene — generating indoor PM2.5 far exceeding WHO limits. Women and children are most exposed.

WHO 2021 Air Quality Guidelines

WHO's 2021 Air Quality Guidelines set annual mean PM2.5 at 5 μg/m³ — the most protective threshold yet — and short-term PM2.5 at 15 μg/m³. Most cities globally exceed these levels dramatically.

Climate and air quality are linked

The fossil fuel combustion that drives climate change also produces PM2.5, NOx and ozone that cause respiratory and cardiovascular disease. Clean energy transitions simultaneously reduce emissions and air pollution deaths.

Key statistics

premature deaths/year (total)

WHO

4.2M

from outdoor air pollution

WHO 2021

3.2M

from household air pollution

WHO 2021

99%

of people breathe unhealthy air

WHO 2022

2.4B

cook with polluting fuels

WHO

5 μg/m³

WHO annual PM2.5 guideline (2021)

WHO AQG 2021

Air pollution deaths by disease type globally (millions) — WHO 2021

Source: WHO. Combined outdoor + household air pollution deaths by primary cause.

Glossary of key terms

PM2.5
WHOFine particulate matter ≤2.5 μm in diameter — the most health-damaging air pollutant, capable of penetrating deep into the lung alveoli and entering the bloodstream. Sources: combustion, industrial emissions, vehicle exhausts, dust, wildfires.

WHO Air Quality Guidelines (AQG)
WHO 2021Evidence-based standards for safe air pollutant concentrations, updated in 2021 with stricter limits. For PM2.5: annual mean 5 μg/m³; 24-hour mean 15 μg/m³. For PM10: annual 15 μg/m³; 24-hour 45 μg/m³.

Household air pollution
WHOIndoor air pollution from burning solid fuels (wood, coal, dung, crop residues, charcoal) or kerosene for cooking and heating. Causes PM2.5 concentrations exceeding outdoor levels by 100-fold in poorly ventilated kitchens.

Ozone (O₃)
WHOA secondary air pollutant formed by photochemical reactions between NOx and VOCs in sunlight. Causes respiratory inflammation, reduces lung function and exacerbates asthma. Also a potent greenhouse gas.

Clean Cooking Alliance
UN FoundationPartnership promoting clean cooking solutions for the 2.4 billion people using polluting fuels. Transitions from open fires to LPG, ethanol, electric or improved biomass stoves substantially reduce PM2.5 exposure.

HEPA filter
WHO/engineeringHigh Efficiency Particulate Air filter — removes 99.97% of particles ≥0.3 μm including PM2.5. Used in air purifiers and ventilation systems to reduce indoor PM2.5 exposure in polluted settings.