New research suggests that air pollution can influence the number of people dying from COVID-19.
The potential connection between air pollution and COVID-19 has been investigated by a team of researchers from Aarhus University in Denmark and University of Siena in Italy.
The study, which was published in Environmental Pollution, found a strong connection between air pollution and COVID-19 death rates in Italy. This also gives a few explanations why that could be the case.
Varying lethality
The rapid spread of the SARS-CoV-2 virus has meant that scientists have had little time to assess what affects its propagation speed and how lethal it can be.
Nevertheless, scientists have already identified some factors which could influence COVID-19’s lethality. Such factors include underlying health problems, the age of an individual and their gender.
We based this information on data gathered from past respiratory disorders or from countries like Italy or China that were exposed to the virus early in life.
Air pollution
The paper’s authors in Environmental Pollution discovered a potential connection not previously discussed by scientists—a similarity between air pollution and the number of COVID-19 deaths.
When they looked at the situation in Italy, the connection was clear.
Italian government official statistics indicate a major difference in the lethality of the virus, depending on geographic areas.
Northern areas in Italy, such as Lombardy or Emilia Romagna, have seen a lethality rate in 12 percent, according to these estimates. The lethality rate was about 4.5 per cent in the rest of the world.
The authors note that these variations can have a number of explications. The discrepancies may be due to the reporting of deaths and illnesses in each region, or to the fact that these two regions had relatively older populations.
The researchers say another potential factor that may explain this difference is air pollution.
In addition to having a considerably higher death rate from COVID-19, Lombardy and Emilia Romagna still have some of the highest rates of air pollution, not just in Italy but throughout Europe.
The researchers drew data from the NASA Aura satellite and the European Environment Agency’s Air Quality Index.
The two datasets give a simple and reliable description of the relative air quality across Europe in different geographic regions.
In addition to being major industrial production centers which are a main cause of air pollution, the authors note that Northern Italy’s geographical and climatic conditions often worsen air pollution. They add that there they are more likely to stagnate than in other parts of the world.
Dysregulated immune systems
A correlation between air pollution and the lethality of COVID-19 doesn’t automatically mean one affects the other. The researchers explain certain factors that may contribute air pollution to the disease’s relative lethality.
Previous study on other diseases contributing to acute respiratory distress syndrome makes it clear that these diseases get dramatically worse as dysregulation of the immune system triggers inflammation in various parts of the body.
The authors further point out that “Air pollution is one of the most well-known causes of chronic inflammation, which ultimately contributes to an innate hyperactivation of the immune system.”
A research in 2016 identified this kind of inflammation in active, non-smoking young people. Another research article related it to the duration of exposure that an person has to air pollution.
On top of that, air pollution destroys a person’s cilia in the lungs. One of the first lines of protection against airborne infection is cilia, which are microscopic, hair-like organelles.
While the authors agree that air pollution in Lombardy and Emilia Romagna may contribute to the higher number of COVID-19 deaths, they emphasize that this is not the whole story.
Scientists need to undertake more work to establish the importance of air pollution and to better understand the other factors which can influence the virus’ lethality.
As Dr. Dario Caro, an environmental scientist at Aarhus University’s Department of Environmental Science in Denmark, explains, “Our considerations must not let us overlook other factors [that may] be responsible for the high lethality reported.”
“[I]mportant co-factors, such as the elevated medium age of the Italian population, the wide differences among Italian regional health systems, ICUs capacity, and how the infects and deaths have been reported have had a paramount role in the lethality of SARS-CoV-2, presumably also more than pollution itself.”
– Dr. Dario Caro
