Only 10 countries have air quality within the WHO standard – 03/19/2024 – Environment

Only 10 countries and territories out of a list of 134 met WHO (World Health Organization) standards for air pollution last year, according to air quality data compiled by IQAir, a Swiss company.

The pollution studied is called fine particulate matter, or PM2.5, because it refers to solid particles less than 2.5 micrometers in size: small enough to enter the bloodstream. PM2.5 is the deadliest form of air pollution, leading to millions of premature deaths each year.

“Air pollution and climate change have the same cause, which is fossil fuels,” said Glory Dolphin Hammes, CEO of IQAir’s North American division.

The World Health Organization sets a guideline that people should breathe no more than 5 micrograms of fine particulate matter per cubic meter of air, on average, over a year. The US Environmental Protection Agency recently proposed tightening the standard from 12 to 9 micrograms per cubic meter.

The few clean air oases that meet WHO guidelines are mainly islands, as well as Australia and the Nordic countries of Europe, Finland and Estonia. Among those that do not reach the recommended standard, where the vast majority of the human population lives, the countries with the worst air quality were mainly those in Asia and Africa.

The four most polluted countries in IQAir’s 2023 rankings — Bangladesh, Pakistan, India and Tajikistan — are in South and Central Asia.

Air quality sensors in almost a third of the region’s cities showed concentrations of fine particulate matter more than ten times above the WHO guideline. This was a proportion “vastly higher than any other region,” the report’s authors wrote.

The researchers pointed to vehicle traffic, coal and industrial emissions, especially from brick kilns, as the main sources of pollution in the region. Farmers seasonally burning their crop residues contribute to the problem, as do households that burn wood and manure for heating and cooking.

China Reversed Recent Gains

One notable change in 2023 was a 6.3% increase in China’s air pollution compared to 2022, after at least five years of improvement. Beijing saw a 14% increase in PM2.5 pollution last year.

The government announced a “war on pollution” in 2014 and had been making progress since then. But the biggest drop in China’s PM2.5 pollution came in 2020, when the pandemic forced much of the country’s economic activity to slow or close. Dolphin Hammes attributed last year’s increase to a reopening economy.

And challenges remain: 11 cities in China reported air pollution levels last year that exceeded WHO guidelines by ten times or more. The worst was Hotan, in Xinjiang.

Big Gaps in the Data

IQAir researchers analyze data from more than 30,000 air quality monitoring stations and sensors in 134 countries, territories and disputed regions. Some of these monitoring stations are run by government agencies, while others are overseen by nonprofit organizations, schools, private companies, and citizen scientists.

There are major gaps in ground-level air quality monitoring in Africa and the Middle East, including regions where satellite data shows some of the highest levels of air pollution on Earth.

As IQAir works to add data from more cities and countries in the coming years, “the worst may be yet to come in terms of what we’re measuring,” Dolphin Hammes said.

Wildfire Smoke: A Growing Problem

Although North America is one of the cleanest regions in the world, in 2023 wildfires burned 4% of Canada’s forests, an area roughly the size of half of Germany, and significantly impaired air quality.

Typically, the list of most polluted cities in North America is dominated by the United States. But last year, the top 13 positions were taken by Canadian cities, many of them in Alberta.

In the United States, cities in the Midwest and Mid-Atlantic states also received significant amounts of PM2.5 pollution from wildfire smoke moving across the border.

Risks of Short-Term Exposure

It’s not just chronic exposure to air pollution that harms people’s health.

For vulnerable people like babies and the elderly, or those with comorbidities, breathing large amounts of fine particulate matter pollution for just a few hours or days can sometimes be deadly. About one million premature deaths per year can be attributed to short-term exposure to PM2.5, according to a recent global study published in The Lancet Planetary Health.

The problem is worst in East and South Asia, as well as West Africa.

Without considering short-term exposures, “we may be underestimating the mortality burden of air pollution,” said Yuming Guo, a professor at Monash University in Melbourne, Australia, and one of the study’s authors.