Air Pollution and Health: The Global Impacts of Fossil Fuels

Our health is strongly influenced by the air we breathe.

Exposure to ambient, or outdoor, air pollution has been linked to a variety of poor health effects. Breathing polluted air for a long period of time (months or years) can make a person more likely to develop or die early from heart disease, chronic lung diseases, lung cancer, respiratory infections, diabetes, and other health problems. It can also make a baby more likely to be  born too early or too small,  which raises their risk of other health problems.  Recent studies  have reported that breathing even low levels of air pollution can result in negative health effects, and the health risks can increase significantly with exposure levels.

Key air pollutants include fine particulate matter (PM _2.5 , or particles smaller than 2.5 micrometers in aerodynamic diameter, and less than a 30 ^th  of the diameter of a human hair), coarse particulate matter (PM ₁₀ ), nitrogen oxides (NO _x ), and ozone (O ₃ ). Among the pollutants, long-term exposure to PM _2.5   has been found to be the most consistent and accurate predictor of poor health outcomes across populations. In 2019, exposure to ambient PM _2.5   was linked to  4 million deaths  worldwide and reduced  global life expectancy by 1 year and 8 months . In addition to the impacts on mortality, exposure to air pollution can contribute to chronic diseases, which can result in high healthcare costs, loss of productivity, and deterioration in quality of life. 

Although 99% of the world is exposed to PM _2.5  levels above the  World Health Organization Air Quality Guidelines , the health impacts of air pollution are not distributed evenly around the world. Explore the map below to see how levels of PM _2.5  and associated health impacts vary around the world.

Sources of air pollution vary across the globe; significant contributors include residential fuel use, energy generation, industries, transportation, agriculture, windblown dust, and waste combustion.

Primary sources of PM _2.5  include anthropogenic, or human-made sources such as fossil fuel (coal, oil, and gas) combustion for energy generation and for the transportation, industry and residential sectors; combustion of solid fuels for cooking and heating; agriculture; waste combustion; and natural sources such as dust. PM _2.5  can also form because of chemical reactions in the atmosphere between emissions from sources such as agriculture, vehicles, and solvent use; this is known as secondary PM _2.5 .

Some of the sources of air pollution, including combustion of fossil fuels and biofuels, are also relevant from the climate perspective; fossil fuels are an important contributor of greenhouse gases, and combustion of both fossil and biofuels is linked to emission of short-lived climate pollutants  (SLCPs)  including black carbon.

Relative contributions of different sources to ambient PM _2.5  vary across the globe. For example, fossil fuel combustion is a large contributor to PM _2.5  levels in countries such as Singapore and South Africa, windblown dust is a major source in many countries of Africa and the Middle East, and across South Asian countries, residential fuel combustion is the largest contributor to PM _2.5  

In 2019, fossil fuel combustion (including coal, oil and gas) contributed to 1.05 million deaths (95% Confidence Interval [CI]: 0.74-1.36 million), 27% of all deaths from outdoor PM _2.5 . The combustion of solid biofuels, such as wood or charcoal for heating and cooking, is another major source of PM _2.5   , and resulted in an additional 740,000 deaths (20%; 95% CI: 0.54-0.99), especially across South Asia and Sub-Saharan Africa.

Windblown dust is another major source, contributing to 620,000 deaths (95% CI: 0.44–0.80) in 2019. In some regions, especially those in proximity to deserts (e.g., Middle East, Sahel in Africa), experience high levels of air pollution due to sources like desert dust or windblown dust. A review of available evidence indicates higher risk of inflammation, and allergic lung diseases like asthma in adults and children as a result of exposure to dust. Evidence on other health effects, including cardiovascular mortality is growing.  More .

Across the world, fossil fuels are used for energy production, residential heating and cooking, transportation, and industrial activities. Thus, if we consider contributions to ambient PM _2.5   and associated health impacts, we find that anthropogenic combustion activities, including use of fossil fuels across sectors and the use of biofuels in the residential sector contribute to nearly 40% of the total global ambient PM _2.5 .

Given this large contribution of fossil fuel combustion on air quality and associated health impacts and the links to climate change, this story map focuses on data on the impacts of fossil fuel combustion on air quality and human health. Furthermore, combustion-related emissions can be managed through targeted interventions and are important components of air quality management strategies.

Note that the data here are for 2019, and are taken from a global analysis. As the energy transition gets underway in countries, and access to clean energy improves, periodic updates will be necessary. For similar data on household air pollution primarily linked to use of biofuels, explore  Hearths and Health , a story map from   Clean Cooking Alliance.  

The story map discusses the impact of fossil fuel combustion on air pollution and the associated health impacts; the impacts on greenhouse gases or short-lived climate pollutants are discussed elsewhere.

Combustion of fossil fuels, including coal, oil, and natural gas, contributed to more than a quarter of all PM _2.5  -related deaths globally in 2019.

Fossil fuel combustion accounts for most of the  global energy demand . Emissions from combustion of coal and liquid fuels (i.e., diesel, gasoline, fuel oil) include particulate matter including black carbon and polycyclic aromatic hydrocarbons, nitrogen oxides (NO _x ), sulfur dioxide (SO ₂ ) and mercury. Gases such as NO _x  and SO ₂  can undergo chemical reactions in the atmosphere to form secondary particles as well.

Coal combustion for energy generation and industrial processes was linked to more than 500,000 deaths, more than half of the total deaths linked to fossil fuel combustion in 2019.

Of the fossil fuels, coal combustion has the largest contribution to global PM _2.5  pollution and associated health impacts. This is not surprising since coal is the most common fuel used for  energy generation globally and is used in many industries including steel, iron and cement.  More than 500,000 deaths worldwide were attributed to PM _2.5  linked to coal combustion in 2019. This large disease burden was regionally stratified with the largest impacts in Southern Africa, Central Europe, and East Asia. Countries with the largest contributions to the disease burden from coal include Eswatini (Swaziland, 43.7% of all PM _2.5  -related deaths) South Africa (36.5%), Botswana (31.2%), Serbia (25.8%), and Bosnia and Herzegovina (23.8%), each with nearly a quarter or more of PM _2.5   deaths linked to coal combustion.

 Indoor emissions from the combustion of coal in households was designated as a Group I carcinogen  (i.e., carcinogenic to humans) by the International Agency for Research on Cancer. Use of coal for energy generation has also been linked to  increased risk of lung cancer.  Exposure to PM _2.5   related to coal burning, and fossil fuel combustion in general, is linked to  cardiovascular diseases.  Furthermore, exposure to air pollution has been linked with respiratory infections and  poor lung function in children. 

Combustion of coal contributes to both poor air quality and greenhouse gas as well as short-lived climate pollutants’ emissions. Technologies such as scrubbers and flue-gas desulfurization can provide some reductions for air pollutants, while carbon capture, utilization, and storage has some potential to reduce greenhouse gas emissions.

In several countries, including the United States, stringent emission controls, use of cleaner technology, and retirement of old power plants has  reduced overall exposures to coal-related PM _2.5   in the last two decades.

Combustion of liquid fuels and gas was linked to more than 13% of air pollution attributed deaths, nearly 50% of the total deaths linked to fossil fuel combustion in 2019.

Globally, liquid fuel and natural gas combustion was linked to 13.2% of PM _2.5   deaths (540,000 deaths) in 2019. In this context, liquid fuels include light, heavy, and diesel oil used in transportation, energy generation, and other commercial and industrial purposes. Of note, natural gas combustion is relatively less polluting compared to coal or oil;  particulate matter emissions from natural gas are also lower compared to coal or oil . For this reason, many countries are switching from coal to natural gas with the goal of improving air quality and reducing carbon dioxide (CO ₂ ) emissions. However, while natural gas combustion does release less CO ₂ , it releases larger quantities of methane (CH ₄ ), a powerful but short-lived climate pollutant, compared to other fuels.

Similar to coal, we see significant regional variability in the impacts of oil and gas combustion on air quality and health. The health impacts are largest in regions including North America, Western Europe, and the Caribbean. For example, in 2019, almost 25% of deaths from PM _2.5   in North America and Western Europe were due to the combustion of liquid fuels and gas.

Air pollution and climate change pose a significant challenge to national and local governments and public health officials, with far-reaching implications for economies and human well-being. The data presented here illustrate the complex interplay between air quality, energy, and climate policies and opportunities for reducing population exposures, providing public health benefits, and mitigating climate change.

This StoryMap is designed by  State of Global Air  with support from the  Clean Air Fund.  It highlights the ways fossil fuels (coal [hard coal, brown coal, and coal coke], liquid fuel [heavy oil, light oil, and diesel oil], and natural gas) contribute to air pollution and poor health around the globe. Health impacts due to occupational exposure are not included in this analysis.

The data found throughout this StoryMap is based on the  State of Global Air 2020  Report and the   HEI Research Report 210,  Global Burden of Disease from Major Air Pollution Sources (GBD-MAPS): A Global Approach. For more information about air quality and health impacts in countries around the world, visit  State of Global Air. 

For more data on PM _2.5  and health trends stretching back to 1990, visit the  State of Global Air Data App . You can also explore the  GBD MAPS database  to find estimated contributions of various sources to PM _2.5  for more than 190 countries around the world.

 Methodology and FAQs 

For questions or to request further data, please email us at contactsoga@healtheffects.org.

HEI contributors include Ada Wright, research assistant, Dr. Pallavi Pant, head of global health; Amy Andreini, science communications specialist; Hope Green, editorial project manager; Kristin Eckles, senior editorial manager; Tom Champoux, director of science communications; Dr. Aaron Cohen, consulting principal scientist; Robert O’Keefe, vice president and Dr. Elena Craft, president.

We would like to thank Dr. Erin McDuffie (US EPA), Dr. Michal Krzyzanowski (Imperial College), Dr. Elizabet Paunovic, Sunil Dahiya (Centre for Research on Energy and Clean Air), Jess Beagley (Global Climate and Health Alliance) and Yasmine Yau and Nina Renshaw (Clean Air Fund) for their valuable comments and feedback. We would also like to thank Dr. Allison Patton and Ayusha Ariana (Health Effects Institute) for their feedback.