Numbers that Take Your Breath Away: COVID-19, Air Pollution, and Equity

April 28, 2020
Mike Marrah/Unsplash
Maria Cecilia Pinto de Moura
Senior Vehicles Engineer

UPDATE 5/1/20:  Since this blog was published, the preliminary study from Harvard mentioned in Section 1 has been updated.  An increase of 1 µg/m3 in long-term exposure to PM2.5 is associated with an 8 percent increase in mortality from COVID-19 in the U.S, instead of the 15 percent originally reported.  As our understanding of COVID continues to evolve, we will learn more about its relationship with air pollution and other potential contributing factors in COVID-19 susceptibility and severity.

The pandemic caused by the novel coronavirus has become a global public health calamity and has spurred the worst economic downturn since the 1930s.  Together, the novelty, the contagiousness and the severity of COVID-19 have quickly turned a few cases into a deadly pandemic.

1.   A small increase in PM2.5 increases COVID-19 mortality

A groundbreaking preliminary study from Harvard is the first to show that an increase of one micron per cubic meter (µg/m3) in long-term exposure to fine particulate matter (PM2.5) is associated with a 15 percent increase in mortality from COVID-19 in the U.S..

This 1 µg/m3 increase is small. To put it in perspective, it is equivalent to the difference between two adjacent counties in New York: Queens and Nassau County.  Also, a decrease in this amount of PM2.5 could prevent 34,000 premature deaths in one year from many diseases.

Before the Harvard study, one other study stood out linking air pollution to increased risk of death from another deadly coronavirus. It showed that the death rate from the Severe Acute Respiratory Syndrome (SARS) more than doubled in areas in China with high exposure of five criteria air pollutants.

2.   PM2.5 is deadly

Exposure to PM2.5 causes or exacerbates many of the same underlying health conditions which increase the risk of death from COVID-19. A large body of scientific evidence attributes adverse health effects to long-term and short-term exposure to PM2.5.

Almost 21 million people live in areas considered to have worse PM2.5 levels than the 12 µg/m3 mandated by the National Ambient Air Quality Standards (NAAQS), About one in six Americans, almost 50 million people, live in areas with too many days of unhealthy levels of particle pollution.

Long-term exposure to PM2.5 can shorten life by one to three years, even in regions that currently meet NAAQS standards, and has been linked to the following adverse health impacts:

Short-term exposure is also dangerous. Peaks of pollution have been linked to premature death from respiratory and cardiovascular diseases. A 2017 study looking at the entire Medicare population, from 2001 to 2012, shows a significant increase risk of death from all causes associated with short-term exposure to PM2.5 and ozone.

3.   What is PM2.5 and where does it come from?

PM2.5 consists of fine particulate matter 2.5 microns in diameter or smaller.  It is responsible for approximately 3.15 million annual premature deaths worldwide. In the U.S., it is the largest environmental health risk factor, responsible for 63 percent of deaths from environmental causes. The particles are small enough to penetrate deeply into the lungs; the smallest can even enter the bloodstream. Understanding where this pollutant originates and how it affects human health is critical.

PM2.5 can be emitted directly through combustion of fossil fuel for transportation, power plants and industries, and biomass in forest fires, and for heating and cooking. Additional PM2.5 can be created in the atmosphere by secondary formation from precursor emissions such as sulfur dioxide, nitrogen oxides, volatile organic compounds and ammonia. Fuel combustion accounts for 85% of airborne particle pollution(the remainder includes dust from road, construction, erosion, vehicle break and tire wear, and other sources).

Decades of discriminatory land-use policies affecting where houses and roads are built, the siting of power plants, waste dumps and manufacturing activity have left communities exposed to contaminated air.  In countries at every income level, diseases caused or exacerbated by all sources of pollution are most prevalent among minority and marginalized communities. More than 4 in 10 people in the U.S. live in counties with unhealthy levels of either particle pollution and/or ozone, and this number is growing.

Mounting evidence shows that exposure levels are higher along busy roads than for a community as a whole, increasing the health impacts for people who live, work or attend schools near roads (more evidence here, here and here).  In a study which maps PM2.5 exposure from the vehicles on our roads, we found that communities of color are exposed to higher levels of PM2.5  than White Americans. In the cleanest areas in the country (see chart), White Americans make up 74 percent of the population, while only making up for 62 percent of the population of the country as a whole. In contrast, in the dirtiest areas, the trend is reversed: African Americans, Latinos, Asians and people of other races make up 61 percent of the people, while these groups represent 38 percent of the country’s population.

Dividing census tracts into quintiles based on PM2.5 exposure reveals significant differences in the racial demographics between the areas with lowest exposure and highest exposure. In the census tracts with highest exposure to particulate matter from on-road vehicles, Latino, African American, and Asian Americans are overrepresented while in the cleanest census tracts, the population has a higher fraction of white residents than the US as a whole.

4.   The virus infects indiscriminately, but kills unevenly

Data by race, now available from 27 states, show that the novel coronavirus is killing people of color disproportionately more than white people. Preliminary data indicate that for every 100,000 Americans, approximately 23 African Americans, 9 White Americans, 9 Latinos and 8 Asian Americans have died from COVID-19.

In most of the 27 states in the American Public Media Research graph (scroll to middle of page), African American deaths from COVID-19 make up a larger percentage of all deaths compared to the share of African Americans in the total population. In Chicago, where African Americans make up 29 percent of the population of the city, a whopping 72 percent of the COVID-19 deaths so far have been African Americans. These numbers are frightening enough to be a clear warning to authorities that immediate action is needed to avoid devastating communities of people of color around the country.

Why are communities of color more vulnerable to COVID-19? Historically, disadvantaged communities have had limited access to factors that are indispensable for good health:  insurance, health facilities, healthy food, clean water and clean air. During the 1918 flu pandemic, African Americans were more likely to die once they got sick because of their greater susceptibility to other diseases, such as pneumonia. Over the years there have been significant legal and political transformations in our society, but communities of color are still suffering from the legacy of decades of discrimination. Housing market dynamics, income and education levels continue to reflect racism and class bias. Communities of color disproportionately face undue burdens due to unemployment, cramped living conditions which make social distancing difficult, obesity and diabetes, drug addiction and crime.  These are the communities who stand to lose the most when disasters strike, from hurricanes and flooding to pandemics. It is no surprise that the projected life expectancy in 2020 for African Americans is lower than for White Americans.

People with pre-existing illnesses, many of which are caused or worsened by air pollution, have a higher risk of dying from COVID-19. Some of these pre-existing diseases, such as hypertension, obesity and diabetes, are particularly prevalent in communities of color. In a study on Chicago, the majority of African Americans who died had hypertension or diabetes.

Obesity is the second-most significant risk factor leading to hospitalization due to COVID-19 (age is the first factor) according to preliminary research in New York City. It is especially alarming that obese young adults are at risk. Obesity is associated with higher risk of heart disease, stroke, type 2 diabetes and some kinds of cancer, and is more common among people of color. Approximately 50% of non-Hispanic African Americans, 45% of Hispanics and 42% of White Americans are obese. Currently more than half of COVID-19 deaths have been in New York and New Jersey, but these findings suggest that other regions where obesity is prevalent and people of color make up a large percentage of the population will soon be seeing a sharp increase in deaths. Obesity is also a significant risk factor for diabetes. In the U.S., African Americans adults are almost twice as likely to develop type 2 diabetes as white adults.

5.   What do we need to do?

 We need to build a strong health system

The crisis has exposed the weaknesses of our health system. In 2018, 27.5 million people, did not have health insurance. Employer-based insurance remains the most common, so the number of uninsured people is surging with unemployment. Under the Affordable Care Act, there was an improvement in coverage for people of color, but between 2010 and 2018 African Americans remained 1.5 times more likely to be uninsured than White Americans. Women and people of color are the overwhelming majority of low-wage workers who have no paid sick leave. With a functional and equitable public health system, we can start to address underlying major health issues, such as obesity and diabetes, which disproportionately affects communities of color.

We need to enforce air pollution regulations

Exactly one week after the Harvard study was made public, the U.S. Environmental Protection Agency announced that it would not strengthen standards for particle air pollution. Current standards have been shown to be inadequate (see above). This announcement flies in the face of all the evidence from the vast body of scientific evidence showing that PM2.5 is responsible for causing or worsening many deadly diseases. This is bad news for everybody, but especially for people of color who are more exposed to PM2.5 from vehicles and are more susceptible to dying from the COVID-19 disease.

A 2017 study showed an increase in all-cause mortality in the Medicare population from a small increase in PM2.5, even at levels below the current annual NAAQS for PM2.5. Some groups—men, African Americans, Asian American and Hispanics, and people eligible for Medicaid—had a higher risk of death compared to the general population. The authors recommend a re-evaluation of the standards.

We need to support science and scientists

There have been other recent efforts to sideline science. The Centers for Disease Control and Prevention (CDC) has been unable to provide science-based advice directly to the public. The ‘restricted science’ proposed rule prevents the EPA from considering scientific studies for which the underlying raw data cannot be made public. This undercuts the ability of science to inform EPA decision-making processes on air pollution and other environmental hazards.

Because the virus is new, there is much uncertainty in ongoing research and the learning curve for scientists has been steep, so this is exactly the wrong moment to sideline science. Scientists are delving through mountains of new data in a desperate attempt to quickly learn about how this new virus spreads, who is at greatest risk, the most effective measures to decrease the rate of infection, the best treatments (also here)  and are rushing to develop a vaccine.

Furthermore, the lack of an organized national effort of coordinated research could be delaying success in developing drugs for treatment and prevention of COVID-19. Insufficient testing has also made it difficult to estimate critical metrics such as mortality and fatality rates, as the number of cases and deaths are undercounted, and there is a legitimate concern among doctors that access to testing for people of color has been harder.

The U.S. government has been called on to release race and ethnicity data, but this effort needs to continue. The vast majority of testing, cases and deaths listed by the CDC does not specify race or ethnicity. This information can better inform a public health response to address the needs of communities of color.

Heroic doctors, nurses, health workers and volunteers are scrambling to accomplish the supremely important task of keeping a large number of patients alive. We cannot afford to sideline science at any time, but doing so in the middle of a public health crisis which is leading to the deaths of tens of thousands of people, especially vulnerable people in communities of color, is heinous.

And finally…

Human beings have been challenged by microorganisms for centuries:  the bubonic plague, smallpox, measles, influenza, Marburg, rabies, HIV, Ebola, dengue, SARS, the Middle East respiratory syndrome, and many others.  We cannot stop the emergence of new microorganisms. However, we can limit the severity of future outbreaks of deadly diseases, and we can reduce and eventually eliminate the disproportionate impact of these diseases on people of color, by building a robust health system for all, strengthening and enforcing air pollution regulations and supporting science and scientists.