People who take Covid-19 are more likely to suffer from severe symptoms if they have been exposed to air pollution for long periods of time.
A study found that people who live in places where there are high levels of the atmospheric pollutant nitrogen dioxide had greater chances of ending up in intensive care units (ICUs) or needing mechanical ventilation after they caught Covid.
Nitrogen dioxide is released into the atmosphere when fossil fuels are burned, and the gas is known to have harmful effects on human lungs. In particular, endothelial cells – which form a thin membrane lining the inside of the heart and blood vessels – are damaged, and this prevents the transfer of oxygen from inhaled breath to human blood.
“Our results show a positive association between long-term exposure to nitrogen dioxide and death of Covid-19 and incidence of Covid-19,” said the team of German researchers led by Susanne Koch of Universitätsmedizin Berlin, a large teaching hospital.
Scientists have previously made links between Covid and air pollution, but few studies have focused on cases that were particularly severe or on underlying health conditions in those affected by the disease.
Koch and her team used air pollution data to calculate average levels of nitrogen dioxide for each district in Germany. The highest was found in Frankfurt, while the lowest was experienced in Suhl, a small county in Thuringia, the group revealed in its report, which was presented last week to Euroanaesthesia, the annual meeting of the European Society of Anesthesiology and Intensive Care in Milan. .
The group also studied data on how many Covid patients in German hospitals required ICU treatment and mechanical ventilation over one month in 2020. These figures were adjusted for other factors, such as pre-existing health conditions.
Analyzing their findings, the team reported that an average of 28 ICU beds and 19 ventilators were needed for Covid patients in each of the 10 counties that had the lowest long-term exposure to nitrogen dioxide. These figures contrasted with an average of 144 ICU beds and 102 ventilators needed in the 10 counties with the highest long-term exposure.
The research has critical implications. In the UK, 75% of urban areas in 2019 had illegal levels of air pollution, emphasizing the fact that the British government has made almost no progress on legal obligations that should have been fulfilled in 2010. During a blockade, there was a temporary decrease in nitrogen in some places. However, traffic and pollution are returning to past levels in many cities and towns.
According to the Royal College of Physicians, air pollution causes the equivalent of 40,000 early deaths a year, and has been linked to cancer, asthma, stroke and heart disease, diabetes, obesity and changes related to dementia. Now there is growing evidence that Covid should be added to this list.
The German study did not show a causal link between air pollution and severe Covid, the researchers said. However, they suggested a credible causal link that could explain the relationship between severe Covid and levels of nitrogen dioxide in the atmosphere.
Coronavirus is known to bind to the Ace-2 receptor when it enters cells after infecting humans. This receptor plays many key roles, one of which involves helping the body regulate levels of angiotensin II, a protein that increases inflammation. In other words, Ace-2 helps stop inflammation.
However, when Covid binds to Ace-2, these brakes are removed. It is also known that air pollution causes a similar release of controls over angiotensin II. So the combination of Covid and prolonged air pollution exposure would lead to more severe inflammation, more severe Covid and more need for ICUs and mechanical ventilation, the team argued.
“Exposure to ambient air pollution can contribute to a variety of other conditions, including heart attacks, strokes, asthma and lung cancer, and will continue to damage health long after the end of the Covid-19 pandemic,” Koch added. “The transition to renewable energy, clean transportation and sustainable agriculture is urgently needed to improve air quality. Reducing emissions will not only help curb the climate crisis, it will improve the health and quality of life of people around the world.”