Polluted Air Makes the Coronavirus Even Deadlier

A preliminary study links more polluted air to higher COVID-19 death rates. It is crucial that we reduce the heavy burden of pollution around the country.

A child rides a scooter through Ken Malloy Harbor Park near the Port of Los Angeles

Ann Johansson for NRDC

The coronavirus pandemic has caused rapid and widespread damage to human health around the world. The toll has been especially heavy on nurses, doctors and other frontline health professionals. Other populations identified as being particularly vulnerable to severe complications from COVID-19 (the disease caused by this new coronavirus) include older adults, people such as cancer patients who have compromised immune systems, and people with chronic heart and lung disease.

Now, new research shows that long-term exposure to air pollution in the U.S. is associated with significantly higher death rates from the coronavirus.

Air Pollution Is a Menace to Public Health

We know that among the people most likely to die from the coronavirus are those who suffer with the kinds of lung diseases, heart troubles, and related ailments worsened by air pollution. Unfortunately, millions of people living in the U.S. already cope with these serious health issues:

  • Asthma: About 25 million people in the U.S., including 6 million children, have asthma. More than 11 million people with asthma, including nearly 3 million children, reported having had one or more asthma attacks in 2018.
  • Chronic Obstructive Pulmonary Disease (COPD): 16 million people suffer from COPD, which describes a group of lung diseases that block airflow and make it difficult to breathe.
  • Lung Cancer: Th e U.S. Environmental Protection Agency recently estimated that, even at current levels, fine particulate matter (PM2.5) air pollution is linked to almost 4,000 lung cancer deaths in the U.S. each year.

Connecting the Dots Between Air Pollution and COVID-19

Air pollution poses major risks to heart and lung health by causing disease and weakening the respiratory system’s ability to fight infections. A prior study of the 2003 SARS outbreak in China identified higher mortality rates from the virus in areas with higher levels of air pollution and because of that finding, public health experts worried that air pollution could play a similar role in worsening health risks from the coronavirus. A study from Italy provided tentative additional evidence of this link.

This new preliminary study, still undergoing peer review and conducted by leading air pollution epidemiologists at Harvard, analyzed long-term air pollution trends across the United States and compared air pollution exposures to coronavirus death rates. Researchers used mortality data available through April 22. It’s the first national study of its kind, incorporating data spanning over 3,000 counties (covering 98 percent of the population) and fine particulate matter (PM2.5) air pollution data from 2000 to 2016. In examining the relationship between air pollution and COVID-19 mortality, the researchers accounted for differences in age, population density, smoking status, body-mass index, income, and education (and other variables).

When they ran the numbers, researchers found that coronavirus death rates were significantly higher in areas with even slightly higher levels of air pollution. For every 1 µg/m3 increase in the long-term PM2.5 air pollution level, the coronavirus mortality rate increased by 8 percent. That’s an important finding, because more than 20 million people currently live in areas that exceed the national ambient air quality annual standard of 12 µg/m3 for PM2.5. Even at that level, EPA recently calculated that this type of air pollution contributes to about 45,000 premature deaths every year.

Racial Disparities in Environmental Health

These findings are important in light of emerging evidence that Hispanics and Black Americans are disproportionately vulnerable to the coronavirus. In Louisiana, for example, African Americans make up a third of the state's population but accounted for about 70% of COVID-19 deaths in the state. Data confirms that air pollution burden is disproportionately higher in disadvantaged communities.

Disparities in air pollution exposures are clearly linked to health inequities. For example, the national asthma burden is disproportionately borne by minority groups and the economically disadvantaged: asthma mortality rates in children and adults are nearly eightfold and threefold higher, respectively, in non-Hispanic blacks than in non-Hispanic whites. In a California study, exposure to polluted air was 2.5 times more likely to send black residents to the emergency room or hospital, compared to white residents. 

Despite nationwide declines in levels of air pollution over time, racial and ethnic disparities in pollution exposures persist and accumulate. That’s why local environmental justice leaders have been denouncing for years the cumulative and unjust burden of socioeconomic and environmental stressors in their communities. Heeding these calls is especially urgent during this time of crisis, as the evidence mounts that COVID-19 harms already vulnerable groups in significant ways. 


Trump Rollbacks Worsen Air Pollution

This research provides compelling new evidence that the heart and lung problems caused by breathing dirty air are making many people more likely to die from the coronavirus. Unfortunately, the Trump administration has worked to roll back common sense protections we already put in place to cut this deadly form of air pollution. By scrapping the Clean Power Plan, halting methane reporting rules, blocking plans to clean up tailpipe pollution from our cars, and giving polluters a free pass to ignore clean air safeguards during this emergency, the Trump agenda is literally making it harder for us all to breathe. Alarmingly, the Trump EPA is widely expected to overrule its own scientists and propose no further strengthening of the national PM2.5 air quality standard within the next few weeks.

Given this reckless assault on our clean air protections, it’s no surprise that the latest data available indicates that air quality in the U.S. has declined since Trump took office, reversing decades of progress in cleaning up our air.

We Need Stronger Clean Air Protections

This new study confirms that breathing dirtier air makes people more likely to die from COVID-19. It’s not politics, it’s science. The data shows that our leaders are putting our people in even more danger at precisely the moment our government should be working to protect us all. In terms of our health, short-term improvements in air quality do not make up for years of damage inflicted by polluted air.

Right now, it’s important that our federal, state, and local public health leaders continue to get the word out—in as many ways and in as many languages as possible—about the serious risks that this virus poses to people with lung and heart problems. Our elected leaders also need to listen to health scientists, not censor them, and strengthen our country’s clean air protections.

There’s a lot we’ve still got to learn about the coronavirus. But when it comes to the links between the pandemic and the heavy burden of air pollution, major health risks are not some distant, invisible threat—sadly, they’re here and now. As we work to address the many challenges triggered by this current pandemic, it’s crucial that we also continue efforts to reduce the heavy burden of air pollution on public health around the country.

Note: This post has been updated to reflect the most current findings from the study as of 4/24/2020.

About the Authors

Vijay Limaye

Staff Scientist, Science Center
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