The role of air pollution in the coronavirus pandemic

Obesity, high blood pressure, & diabetes are all known risk factors. But the poor living in inner cities have another risk to contend with.

Y Rabinovitz ,

Crowded inner cities like Mumbai (pictured) are virtually breeding grounds for coronavirus
Crowded inner cities like Mumbai (pictured) are virtually breeding grounds for coronavirus

From the very outbreak of the coronavirus pandemic, prominent figures appeared in the media to give the general public the presumedly heartwarming message that “we’re all in this together.” Rich and poor alike, they told us, were susceptible, and only by pulling together and making sacrifices for the “greater good” would we emerge from the crisis.

As the mounds of data pile up, however, a very different picture emerges.

Conditions such as obesity, high blood pressure, and diabetes are now known to be significant risk factors with Covid-19 infection. These are all conditions closely linked to poverty and deprivation, with those living in inner-cities especially vulnerable as they often lack both access to and the means of purchasing high-quality fresh produce and rely on cheaper food sources to get by.

And in India, another deadly ingredient is added to the Covid mix – air pollution.

While this also affects many parts of the developed world, India’s cities have long been known as devastatingly polluted as the country races to industrialize and become a first-world power. During India’s lockdown, pollution levels dropped dramatically with factories shuttered and many workers heading back to their villages as employment in the big cities dried up. However, it was always clear that a country like India would not be able to remain in lockdown for long, and now, with its industry revving up again, pollution levels have likewise risen.

According to a study conducted by researchers from Harvard University, an increase of even just one microgram of a certain type of pollutant known as PM 2.5 per cubic meter is linked to an increase of eight percent in the coronavirus fatality rate. The study’s findings have since been replicated in other parts of the world and are no longer a matter of dispute.

“Such pollutants can cause a persistent inflammatory response and increase the risk of infection by viruses that target the respiratory tract,” one of the co-authors of a study conducted by researchers at the University of Cambridge told the BBC. Other studies have shown that exposure to high levels of pollution contribute to the worsening of symptoms in patients with diabetes, high blood pressure, heart disease, and asthma, as well as having a generally detrimental effect on the immune systems even of healthy people.

“The lungs are the gateway to the body,” said Dr. D.J. Christopher, head of pulmonary medicine at the Christian Medical College in Tamil Nadu, India. “Damage to the lungs can cause severe problems and make people more susceptible to Covid-19. It’s like fighting a war with weakened front-line soldiers.”

Mary Prunicki, director of air pollution and health research at Stanford University, pointed to another possible link between coronavirus mortality rates and pollution. “In addition to air pollution’s effect on decreasing immune defenses, it is though that particulate and nitrogen dioxide found in air pollution can act as vectors for the spread and survival of airborne particles such as Covid,” she told the BBC. “One study using mice found that nitrogen dioxide increases the number of receptors to which the virus binds 100-fold.”

Levels of PM 2.5 in India’s capital, Delhi, now average around 12 times above the safe limit defined by the World Health Organization (WHO), with no sign of them dropping any time in the future. Coronavirus levels in India have continued to climb throughout the pandemic, and now stand at just under eight million confirmed cases, with over 114 thousand dead (and these figures are likely grossly underestimated). That is the world’s second-highest caseload, and the third-highest death toll.

All of this is no secret to the Delhi government; an official report has predicted that the capital alone is likely to see 15,000 new cases per day throughout the winter. The government is therefore being urged by health experts to “do something to get pollution levels down.” Leaving aside the near-impossibility of bringing the country to a standstill, it is debatable how much of an impact that would have. Even if air pollution levels in Indian cities drop now, the cumulative effect of years of exposure still means higher risk for city residents – the death toll will continue to rise.