Toxic gases and particle pollution associated with industrial and vehicle emissions are known to worsen viral respiratory infections. In a new study from the Beth Israel Deaconess Medical Center, researchers have confirmed a link between ambient air pollution and worse COVID-19 outcomes.
More than 90 percent of the global population lives in areas where air pollution exceeds levels that are deemed as being safe by the World Health Organization.
The experts reviewed current research on the potential relationships among pollution, respiratory viruses, and health disparities. In a commentary published by the American Thoracic Society, the researchers discuss various ways that the pandemic has highlighted an urgent need to address the global issue of air pollution.
“A multitude of studies show that exposure to higher long-term ambient air pollution is associated with both increased risk of infection and death from COVID-19,” said study co-author Dr. Stephen Andrew Mein.
“Historically, air pollution has been linked with worse health outcomes, including higher mortality, due to other respiratory viruses like influenza. Now, new research on COVID-19 adds further evidence of the adverse effects of ambient air pollution and the urgent need to ad-dress the public health crisis of pollution.”
In one particular study that was reviewed by Dr. Mein and colleagues, researchers at the Harvard T.H. Chan School of Public Health found that each small increase in exposure to long-term fine particle pollution (PM2.5) was associated with an eight percent increase in mortality during the pandemic.
The results of another study suggest that air pollution has contributed 15 percent to COVID-19 mortality worldwide.
“The studies we reviewed evaluated whether long-term, ambient air pollution exposure that occurred years prior to the pandemic was associated with worse COVID-19 outcomes,” said Dr. Mein.
The exact mechanisms of the link between long-term pollution and poor COVID-19 outcomes are not fully understood. One explanation could be that exposure to air pollution impairs the immune system over time, leading to increased susceptibility to viruses as well as more severe viral infections.
The study authors noted that improved air quality during the pandemic may have reduced illness and mortality from non-communicable diseases, but further investigation is needed.
“Research evaluating associations between the dramatic reduction in ambient air pollution during global lock-downs and health care utilization for respiratory conditions would further confirm the impact of ambient air pollution on non-communicable diseases and the need to reduce air pollution to improve overall health,” said study senior author Dr. Mary Rice.
“While the primary association between air pollution and COVID-19 outcomes has been generally consistent, there is still much research to be done.”
“In particular, there is a need for studies that adjust for individual-level risk factors, since cur-rent studies have been restricted to county or municipal-level exposure and outcome data. Research is also needed to evaluate whether air pollution contributes to the stark differences in COVID-19 outcomes among communities of color.”
Inequalities in residential and occupational air pollution exposure may be one of the causes of the stark disparities of the COVID-19 pandemic along racial and ethnic lines. This is because ethnically diverse communities are more likely to live and work in areas closer to industrial pollution.
“The COVID-19 pandemic has highlighted the widespread health consequences of ambient air pollution, including acute effects on respiratory immune defenses and chronic effects that lead to higher risk of chronic cardiopulmonary disease and acute respiratory distress syndrome (ARDS),” said Dr. Mein.
“These chronic health effects likely explain the higher COVID-19 mortality among those exposed to more air pollution. The pandemic has also provided a glimpse into the health benefits of cleaner air.”
“COVID-19 is a wakeup call for the need to adopt stricter air quality standards and end our tolerance for pollution in disadvantaged neighborhoods. As part of our post-COVID-19 recovery, we must clean up the air to improve respiratory health and equality worldwide.”
The study is published in the journal Annals of the American Thoracic Society.