The haze that blurs a blue sky or a beautiful skyline is caused by tiny particles called PM2.5. PM2.5 describes particulate matter, often made from pollution, less than 2.5 microns wide. Despite their microscopic size, PM2.5 are responsible for more than 4 million premature deaths every year. A new study in Nature Communications led by Japanese researchers shows that the pollution caused by consumption in the world’s biggest economies leads to half of those deaths.
Their very small size is what makes PM2.5 so dangerous.
Easily inhalable, they accumulate inside the lungs, where they severely
increase the risk of cancer and other deadly diseases. Yet it is the poor that
are especially vulnerable to PM2.5 and die prematurely.
“Most deaths are in developing countries, and without
international coordination the situation will worsen,” said Dr. Keisuke Nansai,
Research Director at the Material Flow Innovation Research Program of the
National Institute for Environmental Studies in Japan, who had been a visiting
professor at ISA of the University of Sydney, and one of the lead authors of
the study.
While most countries acknowledge they contribute to PM2.5 levels,
there is little agreement on how much and thus their financial responsibility.
In particular, far harder to measure than the direct production of PM2.5 by
factories and cars is the amount caused by consumption.
This is a vital question to answer, says Nansai.
Unlike direct production, which first affects the producing nation and then
spreads across borders to neighbouring nations, the PM2.5 caused by consumption may originate in
distant nations and have negligible effects on the consuming nation.
“Pollution in the form of production emissions creates
a motive to implement joint PM2.5 reduction measures in neighbouring
countries. Such cooperation is unlikely among countries that are geographically
distinct,” said Nansai.
G20 members make up more than three quarters of
international trade and the world’s economic output. Therefore, Nansai and his
colleagues reasoned, 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 around the world, the study mapped out the
emissions made by consumption alone.
The study shows that consumption by the world’s most
consuming nations, such as the U.S. and U.K, causes a significant number of
premature deaths in faraway nations, such as China and India, whereas the
premature deaths caused by production habits are more common in neighbouring
nations like Mexico and Germany.
COVID-19, the pandemic that has changed the world, is
a respiratory disease that is most lethal to the elderly. Similarly, the
premature victims of PM2.5 are also mostly elderly. However, unlike
COVID-19, the study found another group alarmingly susceptible to the PM2.5 produced
by consumption.
“We found that the consumption of G20 nations was
responsible for 78,000 premature deaths of infants [up to 5 years old]
worldwide,” noted Nansai.
The effect was not too great in most G20 nations, such
that the average age of premature deaths was nearly 70 years old. However, in
some countries, namely, South Africa and Saudi Arabia, premature infant death
was so prevalent that the average age of premature deaths was under 60 years
old. Similarly, the average age of premature deaths in India and Indonesia
barely crossed this threshold.
Nansai and his colleagues stress that if consumption
is not considered, then most countries will not think they should pay any
penalty for these deaths.
“As long as responsibility for infant deaths due to
production emissions is the only issue pursued, we can find no rationale for
nations to confront the mass death of infants [in faraway nations],” they write
in the study.
Finally, to emphasize the impact that PM2.5 levels
from consumption level alone has on human health, the study concluded that the
lifetime consumption of 28 people in G20 nations will cause the premature death
of one person worldwide.
Source: https://www.nies.go.jp/whatsnew/20211102-2/20211102-2-e.html
Journal article: https://www.nature.com/articles/s41467-021-26348-y
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