New research suggests that people who experience long-term exposure to air pollution in the US are more likely to die from Covid-19, indicating that dirty air might make the disease even more deadly.
As reported in the journal Science Advances on Wednesday, scientists at Harvard University found higher levels of Covid-19 cases in counties of the US that have higher levels of pollution particles in the air. Furthermore, they worked out that an increase of just one microgram in the long-term average of fine particulate matter (PM2.5) exposure is associated with an 11 percent increase in Covid-19 mortality.
The research looked at Covid-19 mortality rates up to mid-June in 3,089 counties across the US, accounting for 98 percent of the population. They then looked to see how these figures paired up with the estimated daily PM2.5 concentrations between 2000 and 2016. As a caveat to the research, this means they were only able to find concentrations at the area level, not the individual level.
While their study only found a correlation between air pollution and Covid-19 deaths in a given area, the study attempted to take into account factors that might skew the observed links, such as the higher population density of urban areas, demographics, and different morbidity rates across countries.
It’s also hardly surprising to hear that air pollution can aggravate an infectious respiratory disease since inhaling PM2.5 is linked to a greater risk of lung infection. Nevertheless, independent experts remark that it's concerning that even a tiny increase in air pollution appears to have a profound effect on Covid-19 mortality rates.
“It is striking that only small differences in the levels of particles are linked to significantly higher levels of Covid-19,” commented Dr Mark Miller, BHF senior research scientist at the University of Edinburgh in the UK, who was not involved in the study.
“The levels of air pollution in this study were fairly modest,” he added. “Therefore, while this study is carried out in the USA, there is no reason to believe that a similar situation wouldn’t occur in the UK, or anywhere else in the world.”
Another study published last week in the journal Cardiovascular Research found that air pollution contributed to a 15 percent increase in the global Covid-19 mortality rate.
All of this comes hot on the heels of a report released last month that air pollution contributed to around 6,670,000 deaths in 2019, meaning air pollution remains the fourth-leading risk factor for early death worldwide, surpassed only by high blood pressure, smoking, and poor diet. They also estimated that 476,000 babies died in their first month of life last year as a result of complications driven by pollution exposure.
“We now need a better understanding of the biology underlying these associations,” added Miller to Science Media Centre. “Could these findings simply be because both air pollution and covid-19 affect the same vulnerable groups – the elderly and those with respiratory of cardiovascular disease – or is there something more going on? Could coronavirus and air pollution be have additive effects to increase the risk of death in these individuals? Could it be that airborne particles carry the virus or help it gain access to the cells of our body?"
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