COVID-19 mortality and air pollution
Air pollution is an important risk factor for mortality due to COVID-19, finds a recent Harvard study. The study adds to a growing body of research on the health risks from COVID-19 and high air pollution levels.
Harvard researchers evaluated the link between air pollution and COVID-19 mortality. They studied 3,080 counties in the United States, covering 98% of the US population by zip code.
They found that long-term exposure to PM2.5 is associated with worsened severity of COVID-19 infection symptoms and an increased risk of death.
Particularly striking was the finding that even small increases in long term exposure to air pollution were associated with large increases in mortality linked to COVID-19, at a magnitude that was 20 times what would have been estimated.
An increase of 1 mg/m3 in long-term PM2.5 exposure is associated with a 15% increase in the COVID-19 mortality rate,” says the study’s authors.
Similar patterns are seen in Italy and China
Italy, which is already plagued by more than 24,000 deaths due to COVID-19, reveals the same trends as the US. Researchers at the University of Siena pointed out that COVID-19 mortality was 12% in parts of northern Italy - where air pollution is the highest in the country - as compared to 4.5% in the rest of the country. This increased mortality persisted even after correcting for other factors such as age and socioeconomic status. Another research paper by a different group published by the Italian Society of Environmental Medicine suggests that “the rapid increase of contagion rates that has affected some areas of Northern Italy could be tied to atmospheric particulate pollution acting as a carrier and booster there”.
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Reliable data on COVID-19 and air pollution in China is sparse. Nonetheless, scientists at the UCLA’s School of Public Health who analyzed the Sars coronavirus outbreak in China in 2003 found that infected people who lived in areas with more air pollution were twice as likely to die as those in less polluted places. The same is likely true of COVID-19: the more air pollution you are exposed to, the sicker you are likely to get.
Polluted cities in China, Italy, and the USA have higher mortality rates due to COVID-19. Photo credit: Liyao Xie/Getty Images.
Air pollution and the severity of COVID-19 infection: What are the possible causes?
In some people, COVID-19 causes significant damage to the lungs, leading to pneumonia and occasionally a serious condition called severe acute respiratory infection (SARI). The latter carries a high risk of death, even with mechanical ventilation and other advanced life support.
Exposure to air pollution makes the lungs susceptible to infection through several mechanisms. First, pollutants in the air damage to cilia, the microscopic hairs in the upper airways that help keep pathogens out.
Second, air pollution sets off inflammatory reactions in the airways and the lining of the lungs, making it easier for pathogens such as COVID-19 to cause extensive damage.
Third, a still as yet unproven cause, suggested by researchers in Italy, is that microscopic pollutants called particulate matter - PM2.5 and PM10 - act as carriers for the virus, which when inhaled, get transported into the airways and lungs.
Worrisome links between air pollution, coronavirus, and ethnicity
Across the world, low-income and minority communities face the highest mortality from COVID-19 as well as a variety of illnesses linked to air pollution. These groups often live in neighborhoods with poor outdoor air quality – caused by vehicle emissions and polluting industries – as well as poor indoor air quality due to the use of biomass combustion for cooking, poor ventilation, and high levels of mold in low-income housing.
People living in these communities already have higher rates of asthma and other chronic illnesses. When COVID-19 is added, the results can be disastrous.
We see in these big cities higher rates of minority communities suffering from death from COVID-19,” says Donald McEachin, Member of the US House of Representatives (D-VA).
A global respite from air pollution due to the lockdown
Worldwide lockdowns have been a relief for air pollution levels. We can now see and feel what the air was like before vehicle emissions and polluting factories rendered it unfit for breathing.
During the lockdown, residents in Jalandhar (Punjab, India) saw the snow-capped Dhauladhar range – 213 km away – for the first time ever. Photo credit: Twitter/Parveen Kaswan
First China, then Italy, now the UK, Germany and dozens of other countries are experiencing temporary falls in carbon dioxide, nitrogen dioxide, and other dangerous pollutants by as much as 40-50%. In India, major cities have seen a rapid fall in the air quality index (AQI) of more than 40%. This improved air quality is expected to reduce the risks of asthma, heart attacks, and lung disease.
Whether COVID-19 mortality will increase after lockdowns are lifted and air pollution levels go back up is currently unknown.
Nature is sending us a message that if we neglect the planet, we put our own well-being at risk.” - Inger Andersen, Executive Director, United Nations Environment Program
COVID-19 will go away. Eventually.
But will air pollution?
Reducing emissions at the source, increasing energy efficiency, policies to promote renewable energy, and – where needed – technological solutions such as Pure Skies can help reduce air pollution and a large number of diseases it causes.
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