Twindemic: What we know about the link between air pollution, COVID-19

Air pollutants can carry the novel coronavirus’ genetic material; air pollution also increases susceptibility to COVID-19 andother ailments by damaging the heart and lungs in the long-term

By Kiran Pandey
Published: Monday 09 November 2020
‘Twindemic’: What we know about the link between air pollution, COVID-19. Photo: Vikas Choudhary / CSE
Smog over Delhi. Photo: Vikas Choudhary / CSE Smog over Delhi. Photo: Vikas Choudhary / CSE

Public health in India, already in a bad state due to the novel coronavirus disease (COVID-19) pandemic, may worsen as winter takes hold of the northern part of the country, if global studies on the subject are to be believed.

Vehicular and industrial pollution, burning of crop residue, a festive season usually dominated by fireworks, would all worsen an already bad situation over the region as winter — November to February — progresses.

The Air Quality Index (AQI) of Delhi averaged 406 November 6 and 7, according to the Central Pollution Control Board (CPCB).

An AQI of 0-50 is considered ‘good’, 51-100 ‘satisfactory’, 101-200 ‘moderate’, 201-300 ‘poor’, 301-400 ‘very poor’, and 401-500 ‘severe’. Above 500 is the ‘severe-plus or emergency’ category.

Delhi has reported more than 6,000 COVID-19 cases daily in the past few days. Thirteen per cent of this increase has been estimated to be due to air pollution, the Indian Medical Association said November 7.

“This year, we have the double burden of COVID with pollution. Delhi residents’ lungs are compromised due to prolonged exposure to pollution, which is worrisome,” Anumita Roychowdhury, executive director, Centre for Science and Environment said.

According to the National Centre for Disease Control, Delhi is likely to report around 15,000 COVID-19 cases daily in winter because the prevalence of respiratory illnesses during this season worsen the symptoms of the disease.

COVID-19 and air pollution

There have been studies between April and November this year in both, developing and developed countries that have tried to gauge the relationship between COVID-19 and air pollution.

One study, Air pollution aggravating COVID-19 lethality? Exploration in Asian cities using statistical models conducted across nine Asian cities — Delhi, Nagpur, Kanpur, Islamabad, Lahore, Jakarta, Tianjin, Guilin and Hebei — correlated particulate matter (PM) and its ability to transport the coronavirus aerosols (in air) into the respiratory tract of the humans and transmitting infections.

The study, published by Springer, concluded that air pollution was acting as a hidden element in intensifying the impact of COVID-19.

Similarly, a study conducted in Italy, Role of the chronic air pollution levels in the Covid-19 outbreak risk in Italyfound that air pollutants were very much likely to increase COVID-19 transmission in highly polluted places.

It found traces of SARS-CoV-2 RNA, the genetic material of the coronavirus on air pollutants. The study was published in ScienceDirect.

Studies have also concluded that COVID-19 deaths could increase due to long-term exposure to PM.

Two studies in the United States prove that air pollutants like nitrogen dioxide (NO2) and PM 2.5 were likely to enhance populations’ susceptibility to severe COVID-19 death outcomes.

A recent peer-reviewed study published in the journal Science Advances found that long-term exposure to an additional one microgram per cubic metre of fine particulate matter was associated with an 11 per cent increase in death rates from COVID-19.

Titled Air pollution and COVID-19 mortality in the United States: Strengths and limitations of an ecological regression analysis, it was led by Francesca Dominici at Harvard University.

Air pollution is also an ally for COVID-19 in another way. Long-term exposure to air pollution has an effect on the respiratory system including lungs.

People with comorbidities are the most vulnerable, with risks to their lungs and heart because of air pollution. If COVID also causes inflammation, this leads to much more severe illness in these individuals.

When both, long-term exposure to air pollution and infection with the novel coronavirus occur together, there is an additive adverse effect on health, particularly with respect to the heart and blood vessels. This leads to greater vulnerability and less resilience to COVID-19.

What can help?

Besides maintaining hygiene, washing hands and maintaining social distancing, wearing masks is essential to reduce the risk of transmitting COVID-19. 

The use of masks can also cut down exposure to SARS-CoV-2, because the virus-carrying aerosols are in the range of 1–5 micrometre. Mask usage is critical in highly polluted cities to reduce the impact of air pollution, thereby reducing the risk associated with COVID-19.

There is also a need to enforce legislation to reduce levels of air pollution.

Stopping burning of fossil fuels and reducing and controlling emissions from vehicles are other important measures that need to be taken.

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