Air pollution can be fatal for novel coronavirus patients. It is linked to significantly higher death rates in people with COVID-19 as dirty air increases the risk of respiratory problems, as per a recent analysis.
The research, done in the US shows that in the years before the pandemic, even a small, single-unit increase in particle pollution levels is associated with a 15% increase in the death rate. They calculated that slightly cleaner air in Manhattan in the past could have saved hundreds of lives.
People living in polluted areas are much more likely to die from the coronavirus compared to those living in cleaner areas, given the largely varying toxic air levels across countries, the research suggests. As per the scientists, dirty air was already a reason to increase the risk of acute respiratory distress syndrome. It is extremely deadly and can cause COVID-19-related deaths and other respiratory and heart problems.
Scientists in Italy in a separate report notes that the high death rates observed in the north of the country match up with the highest levels of air pollution.
The findings of the scientists could be used to ensure that areas with high air pollution levels take extra precautions for slowing down the spread of the virus and deploy additional resources to tackle the outbreak. The widespread lockdowns have already resulted in fallen air pollution, but as the scientists suggest, ensuring more clear air in the future would help reduce COVID-19 deaths.
The analysis of air pollution and COVID-19 deaths up to 4 April in 3,000 US counties, covering 98% of the population conducted in the study, by researchers at the Harvard TH Chan School of Public Health in Boston. “We found that an increase of only 1μg/m3 in PM2.5 [particles] is associated with a 15% increase in the COVID-19 death rate,” the team concluded.
The risk of death from all causes increases from a small increase in exposure to particle pollution over 15-20 years was already known, but the new work shows that for COVID-19 deaths, this increase is 20 times higher.
“The results are statistically significant and robust,” they said. A range of factors, including poverty levels, smoking, obesity, and the number of COVID-19 tests and hospital beds available, were taken into account in the study. The effect of removing from the analysis, both New York City, which has had several cases and counties with less than 10 confirmed COVID-19 cases, also assessed.
“Previous work showed that air pollution exposure dramatically increased the risk of death from [the] Sars [coronavirus] during the 2003 outbreak,” said Rachel Nethery, one of the Harvard team. “So we think our results here are consistent with those findings.”
Xiao Wu, a fellow team member, said: “This information can help us prepare by encouraging populations [with high pollution exposure] to take extra precautions and allocate extra resources to reduce the risk of poor outcomes from COVID-19. It is likely that COVID-19 will be a part of our lives for quite a long time, despite our hope for a vaccine or treatment. In light of this, we should consider additional measures to protect ourselves from pollution exposure to reduce the COVID-19 death toll.”
The results highlighted the requirement of keeping existing air pollution regulations enforced, and also that failure to do so could potentially increase the COVID-19 death toll, the authors said. They noted that the US Environmental Protection Agency suspended its enforcement of environmental laws on 26 March.
The study is being fast-tracked for publication in a major medical journal.
According to Prof Jonathan Griggs, from the Queen Mary University of London, the study was methodologically sound and plausible, but he mentioned some limitations, including important factors such as the effect of smoking, were not measured at the individual level.
“Clearly, we urgently need more studies, since locally generated particle pollution will bounce back once the lockdown is eased,” he said.
After Italy and Spain, the US has the third-highest death toll to date. A second study focusing on Italy, published in the journal Environmental Pollution, said: “We conclude that the high level of pollution in northern Italy should be considered an additional co-factor of the high level of lethality recorded in that area.”
It noted that northern Italy was one of the most polluted areas in Europe, and the death rate up to 21 March in the north of Lombardy and Emilia-Romagna regions reported was about 12%, compared with 4.5% in the rest of Italy.
“It is well known that pollution impairs the first line of defense of upper airways, namely cilia, thus a subject living in an area with high levels of pollutant is more prone to develop chronic respiratory conditions and [is more vulnerable] to any infective agent,” it said.
There was a warning from Medical scientists that air pollution exposure could make COVID-19 worse in mid-March. Early research on COVID-19 had suggested that as the smokers and former smokers have weakened lungs, they are more susceptible to the virus.
A comprehensive global review published in 2019 found that over long periods air pollution may be damaging every organ and virtually every cell in the human body. However, lockdowns have caused air pollution to fall dramatically.
