A new nationwide study conducted by researchers at Harvard University’s T.H. Chan School of Public Health is the first to show a statistical link between long-term exposure to pollution and COVID-19 death rates.1 The study, which has yet to be peer-reviewed, shows that coronavirus patients living in areas that had high levels of air pollution before the pandemic are more likely to die from the infection than patients living in parts of the country with less air pollution.1
In the analysis, data was collected for approximately 3,000 counties in the United States (98 percent of the population) up to Apr. 4, 2020. The study revealed that higher levels of tiny, dangerous particles in air known as PM2.5 were associated with higher death rates from the COVID-19 infection.
What is PM2.5 ?
PM2.5 is believed to be one of the world’s most dangerous air pollutants. It is made up of tiny particles (smaller than 2.5 micrometers) that can seep into human lungs and bloodstreams.2 The source of PM2.5 is usually automobile exhaust and power plants, as well as toxic fine particle air pollution from burning wood and coal.
Several studies have linked high levels of PM2.5 to heart disease, chronic bronchitis and other respiratory illnesses. It has been estimated that PM2.5 contributed to 4.2 million deaths worldwide in 2015 alone.2
Study: Smallest Increase in PM2.5 Can Increase COVID-19 Death Rates
The Harvard study reveals that even an increase in one microgram per cubic meter of air could potentially increase COVID-19 deaths by 15 percent even accounting for factors like smoking rates and population density.1 For example, the study found that an individual living in a county for decades with high levels of PM2.5 is 15 percent more likely to die from the coronavirus than someone in a region with one unit less of the fine particulate pollution.3
According to Francesca Dominici, PhD, a professor of biostatistics at Harvard University and a principal investigator on the study, “This study provides evidence that counties that have more polluted air will experience higher risks of death for COVID-19.”3
The authors write:
The results of this study also underscore the importance of continuing to enforce existing air pollution regulations during the COVID-19 crisis. Based on our result, we anticipate a failure to do so can potentially increase the COVID-19 death toll and hospitalizations, further burdening our healthcare system and drawing resources away from COVID-19 patients.1
1 Wu X. et al. Exposure to air pollution and COVID-19 mortality in the United States. Harvard University Apr. 5, 2020.
2 Osaka S. Study: The tiniest bit of air pollution makes COVID-19 more deadly. Grist Apr. 9, 2020.
3 Friedman L. New Research Links Air Pollution to Higher Coronavirus Death Rates. The New York Times Apr. 9, 2020.