Just seven countries met World Health Organisation (WHO) standards on international air quality in 2023, according to a new report.
Of 134 countries and regions surveyed, only Australia, Estonia, Finland, Grenada, Iceland, Mauritius and New Zealand are meeting a WHO guideline limit for harmful fine-particle, or PM2.5, pollution – caused by tiny airborne particles expelled by cars, trucks and industrial processes.
Some of the places most affected were in the Middle East, Africa and central and south Asia.
Bangladesh, Pakistan, India, Tajikistan and Burkina Faso ranked as the five countries with the most polluted air in 2023, weighted by population, according to the report by IQAir, a Swiss air quality technology company that collects air-sensor data around the world.
French Polynesia, Mauritius and Iceland had the least air pollution.
The capital cities with the worst air were New Delhi; Dhaka, Bangladesh; Ouagadougou, Burkina Faso; Dushanbe, Tajikistan; and Baghdad, the report found.
Capitals with the lowest concentrations of PM2.5 were mostly in Oceania, Scandinavia and the Caribbean, and included Wellington, New Zealand; Reykjavik, Iceland; and Hamilton, Bermuda.
The IQAir report was based on data from more than 30,000 monitoring stations in 134 countries and regions.
Ireland was ranked 119 out of the 134 countries in terms of 2023 average PM2.5 concentration.
Sources of PM2.5 pollution vary widely, from brick kilns in Bangladesh to mining in Latin America. But the overwhelming source is the burning of fossil fuels such as coal, oil and gas.
Outdoor air pollution, caused primarily by PM2.5, is responsible for the early deaths of more than four million people worldwide each year, according to the WHO.
The particles are “small enough that they can enter different organ systems and the bloodstream; they can irritate the lungs and the respiratory system. And that’s what makes them so detrimental for health,” said Misbath Daouda, an assistant professor of health equity and environmental justice at the University of California at Berkeley who was not involved in IQAir’s analysis.
PM 2.5 pollution is linked to increased rates of heart attack and stroke, and can cause what is known as oxidative stress – essentially, stress that damages the body’s cells faster than they can repair themselves.
Oxidative stress is associated with a variety of illnesses ranging from Parkinson’s disease to cancer.
The impacts of this form of pollution even at modest concentrations are so severe that in 2021, the WHO tightened its recommended guidelines from an average of 10 micrograms per cubic meter to five micrograms per cubic metre today. But IQAir finds very few countries are below this threshold.
Although the report’s overall conclusions are grim, it does note some bright spots. China, for example, after becoming synonymous with poor air quality, has made real strides over the past two decades.
Chile, despite dealing with wildfire smoke last February, reported a 15 per cent decrease in PM2.5 pollution from 2022, and South Africa’s annual average PM2.5 concentration decreased a similar amount. – Agencies