Strong link between coronavirus count, bad air: Study
The analysis is limited to Italy and does not mention how air pollution and testing positive for Covid-19 are linked. Air pollution in Indian cities is among the worst in the world.Updated: Apr 30, 2020 19:48 IST
A University of Verona and Stanford School of Medicine study has found a statistical correlation between highly-polluted areas and Covid-19 infections in Italy, which is among the worst-hit countries by the pandemic. The study, which is yet to be published, has concluded that cities and provinces, where coarse particulate matter (PM 10) exceeded standards for over hundred days a year, were found to be associated with a three-fold higher risk of the disease.
The analysis is limited to Italy and does not mention how air pollution and testing positive for Covid-19 are linked. Air pollution in Indian cities is among the worst in the world; capital New Delhi regularly tops the listing of cities with the worst air. Such studies may give researchers and governments an idea about what to look for, but independent scientists underlined that their conclusions cannot be generalised.
This is the second study from Italy, which has linked air pollution with Covid-19. Air pollution is likely to be a major risk factor for the lethality of Covid 19, scientists from Italy had concluded in a paper that probed whether atmospheric pollution can be considered a co-factor in the extremely high level of SARS-CoV-2, which causes Covid-19, lethality in Northern Italy. The paper was published in Elsevier’s journal of Environmental Pollution on April 4.
Prolonged exposure to air pollution leads to a chronic inflammatory response even among the young and healthy, which makes people living in polluted areas more susceptible to developing complications. The lethality was 12% in Italy’s Lombardy and Emilia Romagna compared to 4.5% in the rest of the country, the study found.
In the latest study, scientists collected air pollution data in Italy from 2019 and the number of Covid-19 cases per province till April 5. The extent of pollution within each specific Italian province was expressed in terms of days per year during which PM 10 or Ozone exceeded their safe levels.
“Since several lines of evidence also attest that Lombardy region has an extraordinarily high level of environmental pollution, we aimed to explore the potential epidemiological association between the number of cases of Covid-19 and environmental pollution in Italy…the association remained statistically significant even when the number of days above pollutant limits was correlated with the number of Covid-19 cases per 1000 inhabitants,” said the latest paper published in Medrxiv, a pre-print server for health sciences on April 27.
Kalpana Balakrishnan, the director of ICMR Centre for Advanced Research on Air Quality, Sri Ramachandra Institute for Higher Education and Research, cautioned against merely looking for a correlation without adjusting for anything, saying it is not helpful. “The paper does not provide a basis for their analysis,” said Balakrishnan. “I note that this paper is not yet peer-reviewed, and is only available as a preprint.”
People with underlying respiratory conditions are more vulnerable to Covid-19 and people in areas with higher air pollution areas are more likely to be affected.
Pallavi Pant, a staff scientist at Boston’s Health Effects Institute, said during the earlier severe acute respiratory syndrome episode in the early 2000s, studies had pointed towards such a relationship. “Ideally, we would like to see multiple studies showing these results for the scientific process to work.”
Pant has been compiling peer-reviewed and pre-print studies on the link between air pollution and Covid-19. Among the peer-reviewed studies, one in Germany based on spatial analysis of nitrogen dioxide pollution on a regional scale and combined with the number of death cases taken from 66 administrative regions in Italy, Spain, France and Germany, also found a relationship between pollution and Covid-19.