Air pollution may increase episodes of coughing, thus spreading Covid, adds US study
While parts of north India battles alarmingly high levels of air pollution, a new analysis of more than 3,000 counties in the US has suggested that people with long-term exposure to PM 2.5 may be more likely to die from Covid-19. The study underlines the fact that higher air pollution may increase episodes of coughing and sneezing spreading Covid-19 faster.
A team of the US researchers, including Xiao Wu from Harvard University, after assessing the impact of long-term exposure to air pollution on Covid-19 death rates in 3,089 counties in the US, found that chronic exposure to PM2.5 pollutants — tiny particles in the air that are two-and-a-half microns or less in width — is linked to greater county-level Covid-19 mortality rates.
The Harvard researchers noted that chronic exposure to PM 2.5 might cause overproduction of ACE-2 receptor proteins in the lungs, which the novel coronavirus uses to enter host cells. They believe prolonged exposure to air pollution might also impair people’s immune system, compromising their abilities to fight off the novel coronavirus infection.
“Chronic exposure to PM2.5 causes alveolar ACE-2 receptor over expression and impairs host defences. This could cause a more severe form of Covid-19 in ACE-2-depleted lungs, increasing the likelihood of poor outcomes, including death,” the Harvard scientists wrote in the study.
But they acknowledged that this is only a hypothesis. The researchers said they were unable to account for individual-level risk factors such as age, race, and smoking status as such data was unavailable.
“This approach leaves us unable to make conclusions regarding individual-level associations,” the scientists said.
The Harvard scientists believe further research on how pollution and other factors may exacerbate Covid-19 symptoms and increase mortality risk is essential to guide policies and behaviour related to the pandemic.
The findings should come as a warning to the authorities here.
For, Delhi’s air quality on Thursday dropped to its worst level since December 2019 with farm fires accounting for 42 per cent of its pollution, the maximum this season so far, according to data from central government agencies. During the same time, it also saw 6,715 reported Covid-19 cases, taking the infection tally to over 4.16 lakh.
The National Centre for Disease Control (NCDC) had warned last week that Delhi may report nearly 15,000 Covid-19 cases daily in winter because of the prevalence of respiratory illnesses during this season that worsen the symptoms of the disease.