Invisible particulate pollution linked to 2m premature deaths

In this Nov 19, 2019 photo, haze covers Sydney as wildfires burn near the city. (RICK RYCROFT / AP)

Microscopic particles in the air caused by pollution have contributed to the premature deaths of two million people, mainly in poor and developing countries, according to a new study.

The study, published by Nature Communications and led by Japanese researchers, shows half the deaths have been caused by consumption in the world's biggest economies.

Particulate pollution, or PM2.5, are particles 2.5 microns or smaller and invisible to the naked eye. Human hair, for example, is 50 microns on average

Particulate pollution, or PM2.5, are particles 2.5 microns or smaller and invisible to the naked eye. Human hair, for example, is 50 microns on average.

Keisuke Nansai, one of the lead authors of the study, said that what makes the particles so dangerous is their size, which enables them to "bypass many of our body's defenses".

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"They accumulate inside the lungs, where they severely increase the risk of ischemic heart disease, chronic obstructive pulmonary disease, stroke, lung cancer and lower respiratory tract infections," said Nansai, research director at the Material Flow Innovation Research Program in Japan's National Institute for Environmental Studies.

He noted the poor are especially vulnerable to PM2.5 and tend to die prematurely.

"Most deaths are in developing countries, and without international coordination, the situation will worsen."

While most countries acknowledge that they contribute to PM2.5 levels, there is little agreement on what form their financial responsibility should take, according to the study.

It added that compared to PM2.5 directly produced by factories and cars, particulate pollution caused by consumption is "far harder to measure".

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In September, the World Health Organization issued "WHO global air quality guidelines", its first update on air quality in 15 years. It said "there is now a much stronger body of evidence to show how air pollution affects different aspects of health at even lower concentrations than previously understood".

Determining the amount of PM2.5 caused by consumption is vital, said Nansai.

"Unlike direct production, which firsts affects the producing nation and then spreads across borders to neighboring nations, the PM2.5 caused by consumption may originate in distant nations and have negligible effects on consuming nations," he said.

Addressing pollution from production emissions may require joint PM2.5 reduction measures in neighboring countries. Such cooperation, the study says, is unlikely among geographically distinct countries.

Nansai and his colleagues reasoned that understanding the impact the consumption of these nations has on PM2.5 levels would provide a reliable benchmark.

Using Eora, a database made nearly a decade earlier to measure global supply chains, the study mapped out emissions from consumption alone.

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The study shows that consumption by the world's greatest consuming nations, including the United States and United Kingdom, causes a significant number of premature deaths in India, China and other faraway nations, whereas in neighboring countries – Mexico and Germany, for example – premature deaths caused by production are more common.

Similar to COVID-19, a respiratory disease most lethal to the elderly, the premature victims of PM2.5 are of advanced age. However, the study found another group alarmingly susceptible to consumption-produced PM2.5.

"We found that the consumption of G20 nations was responsible for 78,000 premature deaths of infants (up to 5 years old) worldwide," Nansai said.

karlwilson@chinadailyapac.com