US Air Pollution Worsens, Potentially Exacerbating COVID-19 Pandemic

Nearly 5 in 10 individuals in the United States—150 million Americans—live where pollution levels are often too dangerous to breathe, according to the American Lung Association’s annual State of the Air Report, released today. Poor air quality has been linked to higher rates of chronic diseases, comorbidities, and poor health outcomes. Several studies suggest poor air quality is a contributing factor to the prevalence of coronavirus disease 2019 (COVID-10) in some communities.

Nearly 5 in 10 individuals in the United States—150 million Americans—live where pollution levels are often too dangerous to breathe, according to the American Lung Association’s annual State of the Air Report, released today.

“Too many cities across the nation increased the number of days when particle pollution, often called ‘soot,’ soared to often record-breaking levels. More cities suffered from higher numbers of days when ground-level ozone, also known as ‘smog,’ reached unhealthy levels,” researchers said.

2020 marks the 50th anniversary of the passage of the Clean Air Act, which aimed to mitigate air pollution through combined efforts of states and the Environmental Protection Agency (EPA). However, this year’s State of the Air Report found that between 2016 and 2018, “more cities had high days of ozone and short-term particle pollution compared to 2015-2017 and many cities measured increased levels of year-round particle pollution.”

Previous studies have shown exposure to air pollution can lead to poor outcomes and high rates of chronic diseases such as Parkinson disease, Alzheimer disease, multiple sclerosis, diabetes, and obesity.

“Almost 70% of the world’s population could be living in urban areas, being continuously exposed to air pollution, by 2050, while cases of dementia are expected to triple. Recent study results highlight the link between cardiovascular disease and dementia, as mediated by long-term exposure to air pollution,” according to an article published on this month.

Combined, the decline in air quality and increase in chronic conditions—resulting, in part, from exposure to pollution—will lead to higher healthcare costs, comorbidity rates, and decreased population health.

Recently, researchers used applied machine learning to predict healthcare utilization based on socioeconomic determinants of care. "The social determinant of health most associated with risk was air quality, which had a relative value more twice that of the next determinant, income,” they reported in a study in the January 2020 issue of The American Journal of Managed Care®.

When it comes to individual cities, the State of The Air Report found that by ozone, year-round particle pollution, and short-term particle pollution, cities in California fared the worst for all 3 categories. In particular, Bakersfield, California, ranked first by year-round particle pollution, second by short-term particle pollution, and third by ozone.

In contrast, a variety of states made up the top slots for cleanest cities based on ozone pollution, year-round particle pollution, and short-term particle pollution.

“This marks the fourth report in a row that worsening air quality threatened the health of more people, despite other protective measures being in place,” researchers said. Regardless of regulatory progress made to reduce pollution from production and manufacturing, climate change remains a key driver increasing pollutants.

“All 3 years ranked among the 5 hottest years in history, increasing high ozone days and widespread wildfires, putting millions more people at risk and adding challenges to the work cities are doing across the nation to clean up,” researchers said.

The American Lung Association listed groups of individuals at greater risk of health complications as a result of breathing polluted air. These groups include:

  • Older and younger Americans
  • Individuals with asthma, chronic obstructive pulmonary disease, lung cancer, or cardiovascular disease
  • Individuals living in poverty
  • Communities of color
  • People who have ever smoked

According to authors, around 74 million people of color live in counties that received at least 1 failing grade for ozone and/or particle pollution. “Over 14 million people of color live in counties that received failing grades on all 3 measures.” Currently, African Americans are 3 times more likely to die from asthma than white individuals, while black children are 10 times more likely to die from the condition than their white counterparts.

These at-risk populations have some overlap with populations at greater risk of suffering severe complications from coronavirus disease 2019 (COVID-19). Some studies have already highlighted the association between exposure to air pollution and prevalence of COVID-19 infections.

Researchers at Harvard University found that “a small increase in long-term exposure to particulate matter (PM2.5) leads to a large increase in COVID-19 death rate, with the magnitude of increase 20 times that observed for PM2.5 and all-cause mortality. The study results underscore the importance of continuing to enforce existing air pollution regulations to protect human health both during and after the COVID-19 crisis.”1 This paper, published ahead of print on MedRxiv, has not yet been peer-reviewed.

In addition, a study conducted on several European countries’ COVID-19 cases found that chronic exposure to tropospheric (ground level) nitrogen dioxide (NO2) “could be an important contributor to the high COVID-19 fatality rates observed in these regions.”2 NO2 is predominately emitted from cars, trucks, buses, power plants, and off-road equipment, according to the EPA. Over short periods of time, exposure to the pollutant can aggravate respiratory illnesses, such as asthma, and long term exposure can contribute to the development of asthma and “potentially increase susceptibility to respiratory infections.”

Researchers noted, “It is now necessary to examine whether the presence of an initial inflammatory condition is related to the response of the immune system to the coronavirus.”

Individuals of color are more likely to be exposed to harmful air pollution than white people, which may help explain why African American populations are disproportionately suffering from the COVID-19 pandemic.

Some maps have shown pollution significantly decreasing as a result of multiple stay-at home or quarantine orders mandated across the country. In a short-term outlook report from the US Energy Information Administration (EIA), researchers found that “after decreasing by 2.7% in 2019…energy-related carbon dioxide (CO2) emissions will decrease by 7.5% in 2020 as the result of the slowing economy and restrictions on business and travel activity related to COVID-19.”

Although this may seem like a silver lining to an otherwise grim moment in history, the Trump administration has taken a more relaxed role in cracking down on environmental infractions perpetrated by industries. Within several months after President Donald Trump took office, the EPA prosecuted fewer alleged violations of air and water regulations, NPR reports.

As part of the administration’s COVID-19 recovery plan, the president is expected to further reduce regulations on businesses, allowing them more flexibility to respond to the pandemic. Last week, the Trump administration rejected stricter air quality standards some EPA scientists recommended in response to the growing body of evidence linking the pandemic to air pollution.

“The United States has some of the cleanest air in the world, and we’re going to keep it that way,” said EPA administrator Andrew Wheeler, according to The Washington Post. “We believe the current standard is protective of public health.”


1. Wu X, Nethery RC, Braun D, et al. Exposure to air pollution and COVID-19 mortality in the United States [published online April 5, 2020]. MedRxiv. doi: 10.1101/2020.04.05.20054502.

2. Ogen Y. Assessing nitrogen dioxide (NO2) levels as a contributing factor to coronavirus (COVID-19) fatality [published online April 11, 2020]. Sci Total Environ. doi: 10.1016/j.scitotenv.2020.138605.