Air pollution raises risk of Covid-19 deaths: Study
Data indicates that there is stagnation of pollutants in the region because of geographical and climatic factors.Updated: Apr 08, 2020 10:35 IST
Air pollution is likely to be a major risk factor for coronavirus disease (Covid-19) mortality, scientists have concluded.
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 chronic respiratory conditions. This theory is borne out by the high Covid-19-related death rates in northern Italy compared to the rest of the country, environmental scientists and physicians in Italy have concluded.
In a paper titled “Can atmospheric pollution be considered a co-factor in extremely high-level of SARS-CoV-2 lethality in Northern Italy?” published in Elsevier’s journal of Environmental Pollution on April 4, the scientists pointed that the mortality was 12% in Lombardy and Emilia Romagna, as compared to 4.5% in the rest of the country. This region is one of Europe’s most polluted based on data from Ozone Monitoring Instrument on the National Aeronautics and Space Administration (NASA)’s Aura satellite.
The data indicates that there is stagnation of pollutants in the region because of geographical and climatic factors. A review of air quality index (AQI), which is calculated based on concentrations of particulate matter and other gases, is also the worst for this region in Italy.
“Air pollution represents one of the most well-known causes of prolonged inflammation, eventually leading to an innate immune system hyper-activation,” the study by scientists at the rheumatology unit of the University of Siena and departmental of environmental science at Arhaus University said. The authors explained how pollutants impact the human immune response.
In a small cohort of mice exposed for three months to fine particulate matter (PM 2.5) showed a significant increase in inflammatory cytokines in both serum and lung parenchyma. High systemic inflammation impairs heart function as well. A high correlation has also been seen between nitrogen dioxide (NO2) and PM in inducing 1L6 (an inflammatory cytokine) hyperexpression.
“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 (intensive care units) capacity and how the infects and deaths have been reported have had a paramount role in the lethality of SARS-CoV-2, (which causes Covid-19) presumably also more than pollution itself,” cautioned environmental scientist Dario Caro in a statement.
The paper has concluded that pollution impairs the first line of defence of the upper airways called cilia (microscopic hair-like structures or organelles) which is why people in polluted areas are more likely to develop chronic respiratory conditions due to an infective agent like SARS-CoV-2.
This was seen during the severe acute respiratory syndrome (SARS) outbreak in 2002 too. A study by scientists of the Fielding School of Public Health analysed five regions with 100 or more SARS cases which showed that the fatality rate increased with the increment in AQI or air pollution levels. Moderate AQIs had an 84% increased risk of dying from SARS compared to those from regions with lower AQI.
“When a population is chronically exposed to high levels of air pollution, the lung is compromised. The lung develops an inflammation. In short, the lung becomes ready for external attack. Those living in areas with cleaner air are more battle-ready. There have bee high cases of chronic obstructive pulmonary disorder (COPD), rhinitis and other conditions, which have manifestations similar to Covid-19. Indian population is extremely vulnerable to rhinoviruses but we’ve grown immunity and come out of it within four to five days. But the unique feature of SARS-CoV-2 is that it can be fatal for some people. This is a great opportunity to study how the impact of a new virus is influenced by air pollution,” said Dr Manas Ranjan Ray, former assistant director of Kolkata-based Chittaranjan National Cancer Institute.
India has some of the most polluted cities in the world, particularly in the Indo-Gangetic plains (IGP) region. People living in the IGP region are expected to lose seven years of their life because of severe air pollution, according to an analysis conducted by the Energy Policy Institute at the University of Chicago (EPIC) released last year.
The analysis said there has been a 72% increase in pollution between 1998 and 2016 in the region which accounts for 40% of the country’s population.