In yet another study linking air pollution with high rate of coronavirus mortality, German researchers have found that elevated levels of nitrogen dioxide in the air may be associated with a high number of deaths from novel coronavirus (COVID-19).
Nitrogen dioxide is an air pollutant that damages the human respiratory tract. For many years it has been known to cause many types of respiratory and cardiovascular diseases in humans.
The study, published in the journal Hypertension, combines satellite data on air pollution and air currents with confirmed deaths related to COVID-19 and reveals that regions with permanently high levels of pollution have significantly more deaths than other regions.
"Since the novel coronavirus also affects the respiratory tract, it is reasonable to assume that there might be a correlation between air pollution and the number of deaths from COVID-19," said study researcher Dr Yaron Ogen from the Martin Luther University Halle-Wittenberg (MLU) in Germany.
In his latest study, the geoscientist combined three sets of data.
This included the levels of regional nitrogen dioxide pollution measured by the European Space Agency's (ESA) Sentinel 5P satellite, which continuously monitors air pollution on earth.
Based on this data, the researchers produced a global overview for regions with high and prolonged amounts of nitrogen dioxide pollution.
"I looked at the values for January and February of this year, before the corona outbreaks in Europe began," explained Ogen.
He combined this data with data from the US weather agency NOAA on vertical airflows. His premise: If air is in motion, the pollutants near the ground are also more disseminated.
However, if the air tends to stay near the ground, this will also apply to the pollutants in the air, which are then more likely be inhaled by humans in greater amounts and thus lead to health problems.
Using this data, the researcher was able to identify hotspots around the world with high levels of air pollution and simultaneously low levels of air movement.
He then compared these with the data on deaths related to COVID-19, specifically analysing the data from Italy, France, Spain and Germany.
It turned out that the regions with a high number of deaths also had particularly high levels of nitrogen dioxide and a particularly low amount of vertical air exchange.
"When we look at Northern Italy, the area around Madrid, and Hubei Provence in China, for example, they all have something in common: they are surrounded by mountains. This makes it even more likely that the air in these regions is stable and pollution levels are higher," Ogen said.
The geoscientist suspects that this persistent air pollution in the affected regions could have led to overall poorer health in the people living there, making them particularly susceptible to the virus.
Earlier, researchers at Harvard University in the US found that even a small increase in long-term exposure to PM2.5, or particulate matter with a diameter of 2.5 micrometers or less, can lead to a large increase in the death rate from COVID-19.