Air pollution may factor in Covid-19 deaths, especially in East Asia

China has 198 million private cars on its roads.
PHOTO: Reuters

Air pollution may contribute to deaths among people suffering from Covid-19, according to new research, which estimates 15 per cent of global fatalities from the respiratory disease could be linked to long-term exposure to carbon emissions and other pollutants.

Researchers, including those from Germany’s Max Planck Institute for Chemistry and the Harvard T.H. Chan School of Public Health, published the findings in the medical journal Cardiovascular Research this week.

The study focuses on long-term exposure to air pollution because it is known to aggravate lung and heart ailments, which are also among conditions that increase the risk of severe or fatal Covid-19 infection, according to health authorities.

“If you already have heart disease, then air pollution and coronavirus infection will cause trouble that can lead to heart attacks, heart failure and stroke,” said study co-author Thomas Munzel from the University Medical Centre at Johannes Gutenberg University in Mainz.

East Asia was the hardest hit of the regions, the researchers estimated, with air pollution contributing to 27 per cent of Covid-19 deaths there. It was also put at 27 per cent in China , the world’s largest carbon emitter.

In Europe, air pollution may have been linked to 19 per cent of deaths, and it was 17 per cent in North America. The pandemic has already taken more than 1.1 million lives.

The researchers noted that their analysis did not mean there was a direct cause and effect relationship between air pollution and dying from Covid-19. Instead they called this a “co-factor” that together could lead to fatalities.

“Since the numbers of deaths from Covid-19 are increasing all the time, it’s not possible to give exact or final numbers of Covid-19 deaths per country that can be attributed to air pollution,” said Jos Lelieveld, of the Max Planck Institute for Chemistry.

“However, as an example, in the UK there have been over 44,000 coronavirus deaths and we estimate that the fraction attributable to air pollution is 14 per cent, meaning that more than 6,100 deaths could be attributed to air pollution,” Lelieveld said.

“In the USA, more than 220,000 Covid deaths with a fraction of 18 per cent yields about 40,000 deaths attributable to air pollution.”

In regions with strict air quality standards and relatively low levels of air pollution, such as Australia, the number of Covid-19 deaths linked to man-made air pollution was just a few percentage points, the researchers said.

This showed that some deaths “could have been largely prevented”, by adopting stricter air quality measures, according to the scientists.

Lao Xiang-qian, an associate professor at Chinese University of Hong Kong’s School of Public Health and Primary Care, said the findings provided more evidence on the importance of reducing air pollution.

“Long-term exposure to air pollution may increase cardiovascular risk – say diabetes and hypertension – and cause cardiovascular diseases and pulmonary diseases.

''If people with these conditions caused by air pollution are infected by Sars-CoV-2, they have a higher chance of dying of Covid-19,” he said, also noting this may be an indirect rather than a direct effect of air pollution.

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The researchers in the latest study used epidemiological data from Covid-19 in the United States and from the 2003 outbreak of a related coronavirus, Sars, in China to make the estimates.

They paired this with ground readings on air quality as well as satellite data showing global exposure to fine particulate matter, usually referred to as PM2.5 or particles measuring 2.5 microns or less.

Such particles, often generated in vehicle exhaust fumes, are about 30 times smaller than the width of a human hair and can penetrate deep into the lungs and damage their function, according to the New York State Department of Health.

The researchers behind the study said the findings may be limited based on country variables and the underlying assumption that the threats from air pollution in Covid-19 are the same as in Sars. A comprehensive evaluation was needed, they said.

But they added that the study provided a case for “substantial benefits from reducing air pollution exposure”, even after the Covid-19 pandemic was brought under control.

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This article was first published in South China Morning Post.