Air pollution can increase the risk of coronavirus deaths as it weakens the immune system of a person, experts say.
According to scientists, constant exposure to air pollution not only makes one vulnerable to Covid-19, but also other kinds of disease, even fatal ones.
Dr Yellapa Reddy, the Governing Council Member of the Foundation for Ecological Security of India, explained that the immune system fights off the diseases in our body. And air pollution hampers that very immune system.
Reddy says that people with a weaker immune system not only catch diseases easily, but that it is also difficult for them to fight against life-threatening ailments.
The Fit India Report 2020 points out that 20.8% of the total people that were surveyed fell sick more than three times a year, indicating low immunity levels.
Bengaluru had 22% of people who fell sick more than three times a year.
The comparison of city-wise data in Fit India report shows that most metro cities which have the highest air pollution levels have the worst immunity.
Among these, Kolkata is worst in terms of immunity as 25% of its people fall sick more than three times a year, followed by Bhubaneswar, Patna, Chandigarh, Lucknow, Bengaluru, Delhi, Mumbai and Pune, among other cities.
A study on air pollution and the case fatality of Severe Acute Respiratory Syndrome (SARS) outbreak in 2003 demonstrated that SARS patients from regions with moderate air pollution had an 84% increased risk of dying from the disease compared to those from regions with low air pollution.
The World Health Organisation (WHO) said that the virus which causes Covid-19 and the one that caused the outbreak of SARS in 2003 were related to each other genetically.
The WHO also said that immunity may also be critical in determining a person's recovery from the novel coronavirus disease.
Like SARS, major deaths from the Covid-19 also are majorly taking place in India's metro cities where people suffer from weak immune systems due to high pollution levels; confirming that air pollution increases the risk of Covid-19 deaths, Dr Reddy says.
According to a study, the exposure to polluted air is linked to decreased function of a gene that appears to increase the severity of asthma in children.
The researchers found that air pollution exposure suppressed the immune system’s regulatory T cells (Treg) and that the decreased level of Treg function was linked to greater severity of asthma symptoms and lower lung capacity.
Treg cells are responsible for putting the brakes on the immune system so that it doesn’t react to non-pathogenic substances in the body that are associated with allergy and asthma. So when Treg function is low, the cells fail to block the inflammatory responses which are the hallmark of asthma symptoms, the study added.
Another study carried out in mice suggested that chronic exposure to particulate matter triggers events that allow white blood cells to escape from bone marrow and work their way into the bloodstream. Their presence in and around blood vessels alters the integrity of vessel walls.
They also collect in fat tissue, where they release chemicals that cause inflammation. This can lead to an increased risk of cardiovascular diseases, diabetes and obesity, as well as other disorders, they study added.
Dr Sylvia Karapagam, a public health expert, believes that the respiratory system has ways of clearing out infections and pollution, while chronic exposure to air pollution increases respiratory morbidity in children and adults, increased hospitalisation as well as mortality rates.
(The author is a Bengaluru-based freelance writer and a member of 101Reporters.com, a pan-India network of grassroots reporters.)