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Science & research / Public health

Regions with persistent dirty air have many more COVID-19 deaths, study finds

By Andrew Sansom 20 Apr 2020 0

Elevated levels of nitrogen dioxide in the air may be linked to a high number of deaths from COVID-19, according to a study by a researcher in Germany.

The study combined satellite data on air pollution and air currents with confirmed deaths related to COVID-19. Its findings reveal that regions with permanently high levels of polluted air have significantly more deaths than other regions. The results were published in the journal Science of the Total Environment.

Nitrogen dioxide is an air pollutant that damages the human respiratory tract and can cause many types of respiratory and cardiovascular diseases in humans. 

“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,” says Dr Yaron Ogen, from the Institute of Geosciences and Geography at Martin Luther University Halle-Wittenberg (MLU). 

Until now, however, there has been an absence of reliable data to investigate this further. 

In this latest study, Dr Ogen combined three sets of data, including 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, he 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,” explains Dr Ogen. He then combined this data with information on vertical air flows from the US weather agency NOAA. 

His premise was that 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 to 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 hotspots with statistics on deaths related to COVID-19, specifically analysing the data from Italy, France, Spain and Germany. It revealed 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. 

Dr Ogen continues: “When we look at Northern Italy, the area around Madrid, and Hubei province 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.”

Dr Ogden’s analysis not only compares countries but is based on individual regions. He suspects that the 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. 

He cautioned, however, that his research is only “an initial indication that there might be a correlation between the level of air pollution, air movement and the severity of the course of the corona outbreaks”, adding that the correlation should now be examined for other regions and set in a broader context.   

‘Assessing nitrogen dioxide (NO2) levels as a contributing factor to the coronavirus (COVID-19) fatality’ is published in Science of the Total Environment