A team of scientists led by Yuming Guo, from Monash University in Melbourne, Australia, recently presented a report on the measurement of PM2.5 pollution particles (the most harmful microparticles for environmental health) in the world, which revealed that Europe and North America have reduced their levels of air pollution, while Asia, Australia, New Zealand, Latin America and the Caribbean have increased in the last 20 years.

Becoming the first global study on air pollution, the results, published in Lancet Planetary Health, indicate that only 0.18% of the earth's surface, which is equivalent to 0.001% of the world's population, lives at levels of pollution considered safe by the World Health Organization (WHO).

Highlighting how the lack of air pollution monitoring stations has impeded data on local, national and global PM2.5 exposures, the team used traditional air quality monitoring observations, weather and air pollution detectors by satellite and statistical and machine learning methods to more accurately assess the concentrations of these microparticles in the world.

Key findings

Among the main results of the report, EFE highlighted that the annual concentration of PM2.5 and the days of high exposure in Europe and North America decreased throughout the two decades of the study, while the exposures increased in the South Asia, Australia, New Zealand, Latin America and the Caribbean.

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Other revelations from the study:

• Despite a slight decrease in PM2.5 high exposure days globally, more than 70% of days in 2019 still had PM2.5 concentrations greater than 15 μg/m³.
• In South and East Asia alone, more than 90% of days had daily PM2.5 concentrations greater than 15 μg/m³.
• Australia and New Zealand saw a marked increase in the number of days with high PM2.5 concentrations in 2019.
• Globally, the annual average PM2.5 from 2000 to 2019 was 32.8 µg/m3.
• The highest concentrations of PM2.5 were recorded in East Asia (50.0 µg/m3) and South Asia (37.2 µg/m3), followed by North Africa (30.1 µg/m3), and the lowest were in Australia and New Zealand (8.5 μg/m³), other regions of Oceania (12.6 μg/m³) and South America (15.6 μg/m³).

The study also shows different seasonal patterns, such as lower levels of pollution in northeast China and northern India during their winter months (December, January and February), and higher levels of PM2.5 in the northern eastern areas of America during the Summer months (June, July and August).

“These data provide in-depth insight into the current state of outdoor air pollution and its impact on human health. With this information, policy makers, public health officials and researchers can better assess the short-and long-term effects of air pollution on health and develop strategies to mitigate it," Guo said.

Deadly pollution

According to the conclusions of the I International Meeting on Environmental Health and Diseases, recently held in Barcelona, air pollution is the direct cause of 9 million deaths each year throughout the world.

"The results are significant, since air pollution is causing 9 million deaths a year in the world, while climate change directly impacts in the death of 500,000 people a year and, indirectly, tens of millions,” said Fernando Valladares, director of the Ecology and Global Change group at the National Museum of Natural Sciences, during his presentation entitled ‘What do we die of?’.

Those attending the event concluded that exposure to pollution during the first year of life and childhood affects different traits of intelligence, performance and cognition, while it contributes to the development of diseases like COPD, asthma, allergies, tumors or alterations in the endocrine system for adults.