COVID-19 outbreak: Cities with higher air pollution at more risk, say experts

Kolkata’s average exposure level was the highest in the country, because of the city’s compactness

By Jayanta Basu
Published: Thursday 26 March 2020
Most people in Kolkata live within 500 metres of busy roads and streets, exposing them to air pollution Photo: Wikimedia Commons

The impact of the novel coronavirus disease (COVID-19) outbreak may be more severe in cities like Kolkata that have high air pollution, according to air pollution experts and physicians.

The immunity of those living in cities with high air pollution is compromised by toxic air, making residents prone to respiratory diseases.

Children and the elderly — who usually have less immunity than others — are more prone to being infected by the novel coronavirus (SARS-CoV-2).

Lung ailments like chronic obstructive pulmonary disease (COPD) were found in old patients who were infected by the virus.

“Elderly people and others who suffer from COPD, asthma or cardio-respiratory problems triggered by air pollution are likely to be affected more by the virus,” said physician Arup Haldar.

Kolkata and its surrounding areas — where nine cases of the infection are reported so far — recorded very high air pollution levels for more than two decades. The city also recorded a higher air quality index value than Delhi for many days during the winter in 2019, though the national capital tops metropolitan cities when it comes to air pollution.

Fine and ultra-fine particulate matter levels — known as PM 10 and PM 2.5, respectively — in Kolkata are usually 150-200 per cent above the safe limits.

This level shoots up by 300-500 per cent during winter.

“People exposed to air pollution for prolonged duration will suffer a more severe impact from the virus than others,” said Raja Dhar, a pulmonologist.

Several patients who did not report any lung ailments are more vulnerable to the virus, said Alok Gopal Ghoshal, another pulmonologist.

It would be disastrous for Kolkata if the COVID-19 disease outbreak reaches the third stage of community infection, according to Amitava Nandy, an expert in tropical diseases.

“The situation may become extremely difficult due to high population density in and around Kolkata, particularly in urban slums,” he said.

Children were also particularly vulnerable for the same reason, said Apurba Ghosh, a paediatrician.

“Scientists had earlier established a clear link between high air pollution exposure and the Severe Acute Respiratory Syndrome (SARS) illness. A similar trend is highly likely for the COVID-19 disease,” said air pollution expert Anumita Roy Choudhury of the Centre for Science and Environment.

Researchers cited the example of the US state of California to prove their point.

The number of infections from SARS-CoV-2 in the state was 1,500, with 27 deaths reported, as on March 22, 2020. Experts partially attribute this to high air pollution levels in the state.

The understanding of widespread damage air pollution causes to health has increased, according to a report in news daily The Guardian. Urban air pollution declined in developed countries, but rose to extreme levels in developing countries like India, the report said.

Patients with chronic lung and heart conditions caused or worsened long-term exposure to air pollution were less able to fight lung infections and were more likely to die, said Sara De Matteis of Cagliari University in Italy, according to the report.

There was evidence from outbreaks like SARS and the Middle East Respiratory Syndrome (MERS) that people exposed to toxic air “are more at risk of dying”, according to the report.

Scientists who studied the SARS outbreak in China found that infected people living in areas with high air pollution were twice more likely to die, compared to those who lived in less polluted areas, according to the report.

Kolkata’s average exposure level was the highest in the country, because of the city’s compactness. Most people in Kolkata also live within 500 metres of busy roads and streets, exposing them to air pollution from predominantly diesel-driven vehicles.

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