Air pollution has increased COVID-19 deaths by at least 15 percent

A new study published by the European Society of Cardiology is the first of its kind to investigate the number of COVID-19 deaths that are linked to air pollution worldwide. The researchers found that long-term exposure to air pollution has increased the global COVID-19 mortality rate by an average of 15 percent.

“When people inhale polluted air, the very small polluting particles, the PM2.5, migrate 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,” said Professor Thomas Münzel. 

“This causes damage to the inner lining of arteries, the endothelium, and leads to the narrowing and stiffening of the arteries. The COVID-19 virus also enters the body via the lungs, causing similar damage to blood vessels, and it is now considered to be an endothelial disease.”

According to the study, approximately 19 percent of COVID-19 deaths in Europe and 27 percent of deaths from the coronavirus in East Asia have resulted from the compounding health impacts of air pollution.

The experts explain that these numbers represent an estimate of the fraction of COVID-19 deaths that could have been avoided without harmful emissions from fossil fuels. The study authors note that this “does not imply a direct cause-effect relationship between air pollution and COVID-19 mortality.” 

Instead, the estimates refer to the relationships between the virus and air pollution that worsen pre-existing health conditions and can lead to fatal outcomes.

The study was focused on data from previous studies in the United States and China which examined the effects of air pollution, COVID-19, and the SARS outbreak in 2003. This information was combined with satellite data on atmospheric PM2.5 concentrations to create a model that could predict the number of coronavirus deaths attributable to long-term PM2.5 exposure. 

Among individual countries, the researchers found that air pollution likely contributed to 29 percent of coronavirus deaths in the Czech Republic, 27 percent in China, 26 percent in Germany, 18 percent in France, and 16 percent in Sweden. Furthermore, three percent of COVID-19 deaths were tied to pollution in Australia, and one percent in New Zealand.

“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 study co-author Professor Jos Lelieveld.

“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%, meaning that more than 6,100 deaths could be attributed to air pollution. In the USA, more than 220,000 COVID deaths with a fraction of 18% yields about 40,000 deaths attributable to air pollution.”

“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 with respect to the heart and blood vessels, which leads to greater vulnerability and less resilience to COVID-19,” said Professor Münzel. “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.”

Previous studies suggest that the fine particulates in air pollution may prolong the atmospheric lifetime of infectious viruses, helping them spread farther. Professor Lelieveld said it is likely that particulate matter plays a role in “super-spreading events” by favoring transmission.

“Particulate matter seems to increase the activity of a receptor on cell surfaces, called ACE-2, that is known to be involved in the way COVID-19 infects cells,” said Professor Münzel. “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.”

The study authors conclude that the findings suggest the potential for substantial benefits from reducing air pollution exposure, even at relatively low PM2.5 levels.

“A lesson from our environmental perspective of the COVID-19 pandemic is that the quest for effective policies to reduce anthropogenic emissions, which cause both air pollution and climate change, needs to be accelerated. The pandemic ends with the vaccination of the population or with herd immunity through extensive infection of the population.” “However, there are no vaccines against poor air quality and climate change. The remedy is to mitigate emissions. The transition to a green economy with clean, renewable energy sources will further both environmental and public health locally through improved air quality and globally by limiting climate change.”

The study is published in the European Heart Journal.

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By Chrissy Sexton, Earth.com Staff Writer