Only seven countries and three territories met the World Health Organization's (WHO) guidelines for fine particulate matter, known as PM2.5, pollution in 2023, according to a report published last week by the Swiss company IQAir, and it has wide-reaching implications for both global health and human health.

What Are Aerosols?

Fine air pollutants, also known as aerosols, are responsible for more than 6 million deaths worldwide each year, according to the World Bank. According to NASA, they result from the burning of fossil fuels and biofuels like wood.

Aerosols profoundly impact climate change as they change the radiative balance of the atmosphere. Essentially, the more aerosols in the air, the less sunlight gets through the atmosphere as more is scattered back into space. While most aerosols cool the planet as a result, just one aerosol, black carbon, actually increases global warming. NASA estimates that since the Industrial Revolution, aerosols that humans have generated have masked as much as 50 percent of the warming that would have occurred thanks to greenhouse gasses. Based on their model, scientists at NASA believe that without the aerosols in the atmosphere, the planet would be approximately 1° C (1.8° F) hotter than it is today.

That’s a scary fact when 2023 was the hottest year on record for much of the globe, leading to increased cooling inequality and cooling poverty, a rise in global ocean temperatures and mass bleaching events, and rising health risks, amongst other issues.

Which Seven Countries Met the WHO Air Pollution Targets?

IQAir is a Swiss company specializing in air quality reports and air purification solutions. The IQAir World Air Quality Report is an annual analysis that tracks global exposure to PM2.5 air pollution, and the company has been running it for the last six years. As more particulate matter sensors and monitors come online around the world, IQAir can collect more precise and accurate data about the quality of our air.

The report highlights what are known as PM2.5 particles, though it does measure other harmful particles, including ozone, nitrogen oxides, sulfur oxides, and carbon monoxide. PM2.5 describes particulate matter that is fine and inhalable. These particles are smaller than 2.5 micrometers, which is where the shorthand PM2.5 comes from. These tiny particles are considered the most harmful form of air pollution to human health, according to the U.S. Environmental Protection Agency (EPA), which monitors and regulates national air quality standards here in the U.S.

According to the annual report, the countries that met the World Health Organization's annual PM2.5 guideline of 5 micrograms per cubic meter were Australia, Estonia, Finland, Grenada, Iceland, Mauritius, and New Zealand. There were also three territories: French Polynesia, Bermuda, and Puerto Rico, which also met the WHO guidelines.

Which Countries Did Not Meet the WHO Targets?

Sadly, the United States is 33rd on the list with an annual average PM2.5 concentration of 9.1 micrograms per cubic meter, well exceeding the 5 microgram per cubic meter WHO guideline. In the U.S. the EPA recently tightened its annual PM2.5 standard from 12 to 9 micrograms per cubic meter, citing health risks like heart attacks, strokes, and premature deaths, particularly affecting disadvantaged communities.

At the opposite end of the spectrum, Bangladesh, Pakistan, and India had the highest PM2.5 levels in 2023, with Bangladesh averaging more than 15 times higher than the WHO guideline. Pakistan is, according to a recent piece in the Washington Post, the "epicenter of a global wave of climate health threats." The paper estimates that more than 500 million people around the world will be exposed to extreme heat for a month or more by 2030, with the largest populations in India and Pakistan. According to Reuters, India and Pakistan are currently facing a heat wave as Bangladesh braces for a cyclone.

A recent study estimated that pollution caused 9 million premature deaths annually between 2015 and 2019, with over 90% occurring in low- and middle-income countries. Deaths from modern pollution risks have risen by 66% since 2000.

While the report from IQAir doesn't detail specific solutions to the growing toxicity of air around the world, there are plenty of solutions that could help improve global air quality, including reducing our reliance on fossil fuels, stricter global emissions rules, expansion of international air quality monitoring systems, clearer guidelines around transboundary pollution, and increased public awareness around air quality issues.

What All This Means for the Long-Term Health of the Globe

The IQAir Report paints a sobering picture of the state of our global air quality: Only seven countries and three territories out of 134 met the World Health Organization's annual guideline, while a staggering 124 nations exceeded it, with the top five most polluted countries averaging over nine times the recommended level.

These figures translate into severe public health impacts globally. PM2.5 exposure increases risks of respiratory diseases, cardiovascular issues, lung cancer, and other illnesses. The WHO estimates ambient air pollution caused 4.2 million premature deaths in 2019 alone, and that disproportionate burden falls on developing nations that lack resources and clean air policies.

The crisis, however, spans all nations. Even in developed economies like the United States (ranked 33rd) and Canada (which, according to IQAir, had the most polluted air in North America in 2023), the annual PM2.5 exceeded WHO's guideline.

Urban PM2.5 levels are projected to rise 68% by 2050 versus 2010 under a business-as-usual scenario, according to the Organization for Economic Cooperation and Development or OECD. Reducing particulate pollution is inextricably linked to mitigating greenhouse gas emissions driving climate change.

Ultimately, the recent report underscores that we have much work to do to improve air quality and stave off global climate change. The question is whether or not we are willing to unite as a global community and make the necessary changes.

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