By: Mihir Vohra, Research Associate

Particulate matter (PM) is a form of air pollution composed of a mixture of dust, chemicals, and liquid droplets. PM is primarily released into the air by industrial facilities that perform mixing and combustion. When people inhale PM in the air, it gets into their lungs and bloodstream, worsening existing lung diseases and even causing lung disease, heart disease, and lung cancer. Very fine particulate matter less then 2.5 micrometers in diameter – called PM2.5 – is especially dangerous. The National Ambient Air Quality Standards has determined that the maximum safe concentration of PM2.5 in outdoor air to be 12 μg/m3, and while the national average measurement of PM2.5 is 8.4 μg/m3, there are some regions in the US where PM2.5 are above this standard. The EPA’s interactive air quality map that shows current PM pollution can be found here.

While our understanding of the COVID-19 virus is still limited, scientific research is already showing that exposure to PM2.5 increases the risk of death from COVID-19. A recent study from the Harvard School of Public Health determined that in the US there is a link between increased PM2.5 in the air and COVID-19 fatality. This link existed even when the researchers controlled for a host of other factors that influence COVID-19 death risk: an area’s population size and density, number of COVID-19 tests performed, number of hospital beds, smoking, body mass index, poverty, income, education, age, race, and weather. This means that the connection between PM2.5 and death from COVID-19 is likely to be real. More concerning than the fact that PM2.5 increases the risk of death from COVID-19 is that the magnitude of the increased risk is very high. The authors calculate that “an increase of only 1 μg/m3 in PM2.5 is associated with an 8% increase in the COVID-19 death rate”, ultimately concluding that “a small increase in long term PM2.5 exposure leads to a large increase in COVID-19 death rate.” Thus existing PM2.5 pollution, even at levels below national health standards, poses serious dangers to Americans during the COVID-19 pandemic.

Research from outside the US seems to corroborate these findings. In Italy, COVID-19 infection and mortality peaked in the spring of 2020, with Northern Italy experiencing particularly high levels of mortality. A recent study discovered that the high level of air pollution in Northern Italy was a factor in causing the high level of mortality relative to the rest of the country. This demonstrates more generally that existing air pollution puts people at risk of death from COVID-19 all over the world.

In the US, COVID-19 fatality is particularly high for people of color. Black and Latinx people are twice as likely to die from COVID-19 as white people. Many factors contribute to this reality, including medical racism and inequities in access to healthcare. However, we should also consider that research shows that Black people disproportionately shoulder the burden of PM-emitting facilities. This means that existing inequities in the impact of pollution are being exacerbated during the COVID-19 pandemic, and that fights to keep communities safe and healthy must include fights to end racial injustice.