Virtually nowhere on Earth is safe from deadly air pollution: study

By Mark Waghorn via SWNS

Virtually nowhere on Earth is safe from deadly air pollution, according to new research.

Only one in 1,000 people live in areas where levels are below those recommended by the World Health Organization.

Toxic particles emitted by traffic and industry are the leading environmental risk factor for disease.

Less than a 50th the width of a human hair, they get into the blood through the lungs - triggering inflammation.

The first study of its kind found only 0.001 and 0.18 of global population and land areas, respectively, come within the limit.

Lead author Professor Yuming Guo, of Monash University in Melbourne, said: "It provides a deep understanding of the current state of outdoor air pollution and its impacts on human health.

"With this information policymakers, public health officials and researchers can better assess the short-term and long-term health effects of air pollution and develop air pollution mitigation strategies."

The international team looked at PM2.5s produced by diesel fumes, wood smoke, brake pads, tyres and road dust. WHO guidelines state they should not exceed 15 micrograms per cubic meter (μg/m³).

Prof Guo and colleagues mapped changes in concentrations across the world over the past two decades.

He said: "In this study, we used an innovative machine learning approach to integrate multiple meteorological and geological information.

"It estimated the global surface-level daily PM2.5 concentrations at a high spatial resolution of approximately 10km×10km for global grid cells in 2000-2019, focusing on areas above 15 μg/m³.

"This is considered the safe limit by WHO. The threshold is still arguable."

The findings fill an important gap. Few monitoring stations globally has meant information on local, national regional and global exposure has been lacking.

They are based on air quality observations and data from satellite-based weather and pollution scanners and AI (artificial intelligence) neural networks.

Over the period the annual average of PM2.5s was 32.8 µg/m3 - over twice the legal limit.

High exposure days in Europe and the U.S. fell - but rose in southern Asia, Australia, New Zealand, Latin America and the Caribbean.

By 2019 PM2.5s were above 15 μg/m³ 70 percent of the time - soaring to over 90 percent in southern and eastern Asia.

The highest concentrations were in Eastern Asia (50.0 µg/m3), Southern Asia (37.2 µg/m3), followed by northern Africa (30.1 µg/m3).

The analysis in Lancet Planetary Health also identified alarming seasonal patterns, said prof Guo.

For instance Northeast China and Vorth India had unsafe levels during their winter months of December, January and February, while eastern areas of northern America were worst hit in June, July and August - their summer.

Prof. Guo said: "We also recorded relatively high PM2.5 air pollution in August and September in South America and from June to September in sub-Saharan Africa."

Australia and New Zealand (8.5 μg/m³), other regions in Oceania (12.6) and South America (15.6) had the lowest annual concentrations.

Last week a study found even PM2.5 exposures of between 12.0 and 13.9 μg/m³ raise the risk of dying from cardiovascular disease by 16 percent.

Scientists in the U.S. called for a new standard limit of 8 μg/m³.

Air pollution kills an estimated 1.8 million people across the world each year. It is also behind nearly two million cases of childhood asthma.

In 2013, PM2.5s were classed as a carcinogen by the International Agency for Research on Cancer. They were also implicated in increasing the risk of Covid.