Particulate air pollution remains the greatest external risk to human health, but most of its impact on global life expectancy is concentrated in just six countries, with Bangladesh being one of the most polluted in the world.

As global pollution edged upward in 2021, so did its burden on human health, according to new data from the Air Quality Life Index (AQLI).

If the world were to permanently reduce fine particulate pollution (PM2.5) to meet the World Health Organization's (WHO) guideline, the average person would add 2.3 years onto their life expectancy-or a combined 17.8 billion life-years saved worldwide.

This data makes clear that particulate pollution remains the world's greatest external risk to human health, with the impact on life expectancy comparable to that of smoking, more than 3 times that of alcohol use and unsafe water, and more than 5 times that of transport injuries like car crashes. Yet, the pollution challenge worldwide is vastly unequal.

In no other location on the planet is the deadly impact of pollution more visible than in South Asia, home to the four most polluted countries in the world and nearly a quarter of the global population.

In Bangladesh, India, Nepal and Pakistan, the AQLI data reveal that residents are expected to lose about 5 years off their lives on average if the current high levels of pollution persist.

"Three-quarters of air pollution's impact on global life expectancy occurs in just six countries, Bangladesh, India, Pakistan, China, Nigeria and Indonesia, where people lose one to more than six years off their lives because of the air they breathe," said Michael Greenstone, the Milton Friedman Distinguished Service Professor in Economics and creator of the AQLI along with colleagues at the Energy Policy Institute in University of Chicago (EPIC).

For the last five years, the AQLI's local information on air quality and its health consequences has generated substantial media and political coverage, but there is an opportunity to complement this annual information with more frequent-for example, daily-and locally generated data.

Indeed, many polluted countries lack basic air pollution infrastructure. Asia and Africa are the two most poignant examples.

They contribute 92.7 percent of life-years lost due to pollution. Yet, just 6.8 and 3.7 percent of governments in Asia and Africa, respectively, provide their citizens with fully open air quality data.

Furthermore, just 35.6 and 4.9 percent of countries in Asia and Africa, respectively, have air quality standards-the most basic building block for policies.

The collective current investments in global air quality infrastructure also do not match where air pollution is having its greatest toll on human life. While there is a large global fund for HIV/AIDS, malaria, and tuberculosis that annually disburses USD 4 billion towards the issues, there is no equivalent set of coordinated resources for air pollution.

In fact, the entire continent of Africa receives under USD 300,000 in philanthropic funds towards air pollution (i.e. the current average price of a single-family home in the United States).

Only USD 1.4 million goes to Asia, outside of China and India. Europe, the United States, and Canada, meanwhile, receive USD 34 million, according to the Clean Air Fund.

"Timely, reliable, open air quality data in particular can be the backbone of civil society and government's clean air efforts-providing the information that people and governments lack and that allows for more informed policy decisions," said Christa Hasenkopf, the director of AQLI and air quality programs at EPIC.

"Fortunately, we see an immense opportunity to play a role in reversing this by better targeting-and increasing-our funding dollars to collaboratively build the infrastructure that is missing today," she added.

China

Although the challenge of reducing air pollution across the world may seem daunting, China has had remarkable success, reducing pollution by 42.3 percent since 2013, the year before the country began a "war against pollution."

Due to these improvements, the average Chinese citizen can expect to live 2.2 years longer, provided the reductions are sustained. However, the pollution in China is still six times higher than the WHO guideline, taking 2.5 years off life expectancy.

Southeast Asia

Like South Asia, almost all of Southeast Asia (99.9 percent) is now considered to have unsafe levels of pollution, with pollution increasing in a single year by as much as 25 percent in some regions. Residents living in the most polluted parts of Southeast Asia are expected to lose 2 to 3 years of life expectancy on average.

Central and West Africa

While Asian countries rightly receive the most media coverage about extreme levels of air pollution, the African countries of the Democratic Republic of Congo, Rwanda, Burundi, and the Republic of Congo are amongst the ten most polluted countries in the world. In the most polluted areas of these regions, pollution levels are 12 times the WHO guideline and taking as much as 5.4 years off lives-becoming as much of a health threat as well-known killers in the region like HIV/AIDS and malaria.

Latin America

While average air quality is at an unsafe but relatively low level across the region, the most polluted areas-located within Guatemala, Bolivia, and Peru-experience air quality similar to pollution hotspots like Pune in India and Harbin in China. In these regions, the average resident would gain 3 to 4.4 years of life expectancy if their air quality met the WHO guideline.

United States

In the United States, Americans are exposed to 64.9 percent less particulate pollution than in 1970-prior to the passage of the Clean Air Act-and they're living 1.4 years longer because of it. Yet, 96 percent of the country still doesn't meet the WHO's new guideline of 5 µg/m³. This year, the EPA proposed to lower the national standard from 12 μg/m³ to 9-10 µg/m³, gaining 3.2 million total life years if the upper limit of that proposed standard were met. In 2021, 20 out of the top 30 most polluted counties were in California due to the impact of wildfires.

Europe

In Europe, residents are exposed to about 23.5 percent less pollution than they were in 1998, soon after the Air Quality Framework Directive started, gaining 4.5 months of life expectancy because of it. Yet, 98.4 percent of Europe still doesn't meet the WHO's new guideline. In 2022, the EU proposed ratcheting down their standard of 25 µg/m³ to 10 µg/m³ by 2030, gaining 80.3 million total life years if the proposed standard were met. Residents in eastern Europe are living 7.2 months less than their western neighbors due to dirtier air.