Residents of Paris, London, Los Angeles and Hong Kong are breathing cleaner air than a year ago, while N’Djamena, Baghdad and New Delhi are suffering higher levels of pollution, the latest report on global air quality shows.
Roughly 90 per cent of the world’s population is still breathing air that poses a risk to health but the gap between high and low income cities is widening, the annual study by IQAir, the Swiss-based air technology group found, using 30,000 ground level sensors from more than 7,000 cities.
The study measured the concentration of fine particulate matter with diameters of up to 2.5 microns, known as PM2.5, one of the most hazardous pollutants as it may be able to enter the bloodstream.
In richer countries, air quality was improved where industry was complying with stricter World Health Organization guidelines, and transport was being electrified, it concluded, but developing countries were struggling.
“Biomass and agricultural burning are the number one reason for stubbornly high air pollution levels in the developing world,” said Frank Hammes, IQAir chief executive.
In Europe, where Berlin and Rome had slightly worse air quality levels in 2022, household burning of wood accounted for a large proportion of winter smog.
China had managed to achieve impressive reductions in air pollution for the past seven years, Hammes said, based on a crackdown on polluting industry and a focus on renewable energy and electric vehicles, though continued burning of coal still caused serious air pollution.
In the most recent year, China’s air quality improved as extensive Covid lockdowns suppressed economic activity, leading to lower emissions.
“In 2023, it remains to be seen if China can further reduce air pollution, or if the pressure of increased economic activity leads to stagnation or an increase in air pollution,” Hammes cautioned.
The WHO estimates that poor air quality accounts for 7mn preventable deaths a year, while the World Bank has put the economic cost at more than $8tn.
New Delhi and Baghdad’s concentration of pollutants in 2022 were almost 18 times higher than the maximum safe level recommended by the WHO.
N’Djamena in Chad, one of the poorest countries in the world, earned the dubious accolade of being the most polluted capital, replacing New Delhi even though air quality there also continued to deteriorate. The surge in PM2.5 concentration in N’Djamena was attributed to massive dust storms from the Sahara Desert, the report found.
India remains host to 12 of the top 15 most polluted cities in the central and south Asia regions.
Vietnam’s capital Hanoi reported the second worst air quality in south-east Asia and was in the bottom 18 globally. Vietnam has been expanding its industrial activity rapidly in recent years as big tech companies such as Apple, Google, Dell and their suppliers invest in new factories to diversify away from China.
Several Middle Eastern capitals ranked among the 20 most polluted cities globally. These included Abu Dhabi, Riyadh and Doha, which all saw air quality worsen in 2022.
Meanwhile, Canberra in Australia overtook Nouméa, in the Pacific island of New Caledonia, to report the world’s best air quality last year. Fewer fires and dust storms helped to deliver its residents cleaner air, researchers found.
Other nations among the 13 out of 131 surveyed that met WHO’s air quality guidelines included Guam, New Zealand, Estonia, and Finland. Of the cities surveyed, Hamilton in Bermuda, Puerto Rico’s San Juan and Reykjavik in Iceland had the freshest air.