Researchers from the University of Siena in Italy and Aarhus University in Denmark are suggesting that the high level of pollution in Northern Italy should be considered an additional co-factor of the high level of COVID-19 fatalities recorded in that area. An open-access paper on their work is published in the journal Environmental Pollution.

The course of COVID-19 differs for patients the world over: many experience flu-like symptoms, while many others need hospital treatment for acute respiratory infection that, in some cases, leads to death.

What factors affect the course of the disease and the possibilities to combat COVID-19 remains unclear, as long as there is no medical treatment or vaccine.

The COVID-19 mortality rate is up to 12% in the northern part of Italy, while it is only approx. 4.5% in the rest of the country. Lombardy and Emilia Romagna are Italian regions with both the highest level of virus lethality in the world and one of Europe’s most polluted areas.

The researchers used data from the NASA Aura satellite, which has demonstrated very high levels of air pollution across precisely these two regions. The team compared these data with the Air Quality Index—a measurement of air quality developed by the European Environment Agency. The index gathers data from several thousand measuring stations all over Europe, providing a geographical insight into the prevalence of a number of pollutant sources in the EU.

The team provided evidence that people living in such an area with high levels of pollutant are more prone to develop chronic respiratory conditions and suitable to any infective agent. Moreover, a prolonged exposure to air pollution leads to a chronic inflammatory stimulus, even in young and healthy subjects.

There are several factors affecting the course of patients’ illness, and all over the world we’re finding links and explanations of what is important. It’s very important to stress that our results are not a counter-argument to the findings already made. At the moment, all new knowledge is valuable for science and the authorities, and I consider our work as a supplement to the pool of knowledge about the factors that are important for the course of patients’ illness.

Our considerations must not let us neglect other factors responsible of the high lethality recorded: important 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 has been reported have had a paramount role in the lethality of SARS-CoV-2, presumably also more than pollution itself.

All over the world, we’re seeing different approaches from countries’ authorities, in countries’ general public health outset and in the standards and readiness of different countries’ national healthcare systems. But this doesn’t explain the prevalence and mortality rates that we’re seeing in northern Italy compared with the rest of Italy. This feeds hope that we may have found yet another factor in understanding the high mortality rate of the disease in northern Italy.

—Dario Caro, corresponding author

Resources

• Edoardo Conticini, Bruno Frediani, Dario Caro (2020) “Can atmospheric pollution be considered a co-factor in extremely high level of SARS-CoV-2 lethality in Northern Italy?” Environmental Pollution, doi: 10.1016/j.envpol.2020.114465