Air pollution link in 15% of Covid-19 deaths

About 15% of global deaths from Covid-19 could be attributed to long-term exposure to ambient fine particulate air pollution, a landmark new study has found.

A team of researchers from Germany and Cyprus have, for the first time, estimated the proportion of deaths from the novel coronavirus that could be ascribed to the health effects of poor air quality. The findings were published in the journal Cardiovascular Research.

In Europe, the proportion of deaths amounted to about 19%; North

America, 17%; and East

Asia, 27%.

The “attributable fraction’’ does not imply a direct cause and effect relationship between air pollution and Covid-19 mortality ( although it is possible). Instead, it refers to the relationship between the two — direct and indirect — by aggravating comorbidities that could lead to fatal health outcomes from being infected with the virus.

The researchers used epidemiological data from previous United

States and Chinese studies of air pollution and

Covid-19 and the severe acute respiratory syndrome outbreak in 2003, supported by additional data from Italy.

This was combined with satellite data showing global exposure to polluting fine particles

(PM2.5), information on atmospheric conditions, and ground-based pollution-monitoring networks. This was used to create a model to calculate the fraction of coronavirus deaths that could be attributable to longterm exposure to PM2.5.

The results are based on epidemiological data collected up to the third week in June this year.

Particulate matter, they found, seems to increase the activity of a receptor on cell surfaces, called

ACE-2, which is known to be involved in the way

Covid-19 infects cells.

“So we have a ‘ double hit’: air pollution damages the lungs and increases the activity of ACE-2, which in turn leads to enhanced uptake of the virus by the lungs and probably by the blood vessels and the heart,” says co- author, professor

Thomas Münzel from the University Medical

Center of the Johannes Gutenberg University,

Mainz, in a statement.

A new, though preliminary finding, is that a significant fraction of worldwide Covid-19 mortality is attributable to air pollution, of which up to 60% is related to the use of fossil fuels. “This represents potentially avoidable, excess mortality,” the authors write.

Münzel explains that when people inhale polluted air, very small polluting particles, “the PM2.5, migrates from the lungs to the blood and blood vessels, causing inflammation and severe oxidative stress, which is an imbalance between free radicals and oxidants in the body that normally repair damage to cells”.

This damages the inner lining of arteries — the endothelium — leading to the narrowing and stiffening of the arteries. “The Covid-19 virus also enters the body through the lungs, causing similar damage to blood vessels, and it is now considered to be an endothelial disease. If both long-term exposure to air pollution and infection with the Covid-19 virus come together then we have an additive adverse effect on health, particularly concerning the heart and blood vessels, which leads to greater vulnerability and less resilience to Covid-19. 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.”

The researchers emphasise that the data in the study is from uppermiddle and high-income countries, and the representativeness of results for low-income countries may be limited. “It will be critical to collect epidemiological evidence from many regions with different socioeconomic and environmental conditions, to support analyses of the Covid-19 pandemic and investigate the role of environmental factors.”