About 15% of global Covid-19 deaths may be linked to air pollution, according to a new study published on Tuesday. In East Asia, about 27% of the deaths could be attributed to long-term exposure to air pollution, while it was 19% in Europe and 17% in North America.
The study was published in Cardiovascular Research by researchers from Germany and Cyprus. They said that these figures were an estimate of “the fraction of Covid-19 deaths that could be avoided if the population were exposed to lower counterfactual air pollution levels without fossil fuel-related and other anthropogenic (caused by humans) emissions”.
However, they added that this does not imply a direct cause-effect relationship between air pollution and Covid-19 deaths – although it is possible. “Instead it refers to relationships between two, direct and indirect, i.e. by aggravating co-morbidities (other health conditions) that could lead to fatal health outcomes of the virus infection,” the researchers said.
Globally, the coronavirus has infected more than 4.34 crore people and killed 11,58,882, according to the Johns Hopkins University. In India, as many as 79,46,429 people have been infected by the virus, while 1,19,502 have died. The United States is the worst affected country in the world, with 87,02,750 cases and 2,25,706 deaths.
According to the study, air pollution contributed to 29% of coronavirus deaths in the Czech Republic, 27% in China, 26% in Germany, 22% in Switzerland, 21% in Belgium, 19% in the Netherlands, 18% in France, 16% in Sweden, 15% in Italy, 14% in the UK, 12% in Brazil, 11% in Portugal, 8% in the Republic of Ireland, 6% in Israel, 3% in Australia and 1% in New Zealand.
The study used data from the US and China relating to air pollution, Covid-19 and the SARS outbreak in 2003 as well as additional data from Italy, according to a statement by the European Society of Cardiology. The researchers combined this with satellite data showing global exposure to PM2.5 – the most dangerous and common pollutants with a diameter of less than 2.5 microns – as well as information on atmospheric conditions and ground-based pollution monitoring networks, till June 2020. Long-term exposure to PM2.5 increases risk of illness and death from cardiovascular and pulmonary disorders.
“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 Professor Jos Lelieveld of the Max Planck Institute for Chemistry in Germany and the Cyprus Institute Nicosia, Cyprus.
“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,” he said. Similarly, in the US, about 40,000 deaths could be attributed to air pollution.
The research team included Professor Jos Lelieveld, Professor Thomas Munzel from the University Medical Center of the Johannes Gutenberg University, Mainz, and the German Center for Cardiovascular Research, Mainz, and Dr Andrea Pozzer from the Max Planck Institute for Chemistry.
“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. 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.”— Professor Thomas Munzel.
“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,” Professor Munzel said. “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.”
“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. 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.”— Professor Thomas Munzel
The researchers said that the results showed that there was potential for “substantial benefits” from reducing air pollution.
“The pandemic ends with the vaccination of the population or with herd immunity through extensive infection of the population,” they said. “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.”