Berlin, 14 March 2023 (dpa/MIA) — Almost the entire global population breathes polluted air, with only 0.001% living in places where fine particulate matter levels are not exceeding annual air quality limits, new research has found.

On average across the globe, the daily limit of exposure to ambient PM2.5 particles recommend by the World Health Organization (WHO) was exceeded on more than 70% of days in 2019, according to findings published in The Lancet Planetary Health journal.

PM2.5 particles are fine particulate matter with a diameter of less than 2.5 micrometres - a unit of length that equals 1 thousandth of a millimetre.

The WHO had lowered its recommended mean annual exposure limit for PM2.5 from 10 to 5 micrograms (thousandths of a gram) per cubic metre of air in 2021.

For their study, the research group led by Yuming Guo from Melbourne's Monash University determined particulate matter pollution on the basis of measured values and computer models for the years from 2000 to 2019.

According to their findings, the global PM2.5 annual average was 32.8 micrograms per cubic metre of air, with the highest value measured in East Asia, at 50, followed by South Asia with 37.2 and North Africa with 30.1.

PM2.5 levels were lowest in Australia and New Zealand (8.5), the rest of Oceania (12.6) and South America (15.6).

The daily maximum value of 15 micrograms per cubic metre of air recommended by the WHO was exceeded on more than 70% of all days worldwide, and on more than 90% of all days in East and South Asia.

Fine particulate matter levels only decreased in Europe and some regions of North America and Africa, the researchers found.

While daily ambient air pollution limits were still exceeded in Europe on 60% of days in 2000, that was only the case on 25% of days in 2019.

According to the WHO, some 7 million people worldwide die prematurely each year due to ambient air pollution.