Prior exposure to air pollution increases risk of death from COVID-19, new research suggests

Living on Earth
Los Angeles smog

Los Angeles, California, on a smoggy day.

Emerging research indicates the novel coronavirus is deadlier to people with long-term exposure to high air pollution and hits minority communities particularly hard.

Biostatisticians at Harvard’s T.H. Chan School of Public Health compared death rates from COVID-19 with air quality records in 3,000 counties. They found that in areas with just a small increase in long-term rates of fine particle pollution, 15% more people are likely to be killed by the virus.

Researchers at the University of Siena in northern Italy also suggest there is an association between the region’s long history of high air pollution and the high pandemic death rates.

RelatedWhat can COVID-19 teach us about the global climate crisis?

Fine particle air pollution is any type of matter that is suspended in the air. It can come from burning wood, ground up gravel that rises into the air, dust, even salt that gets washed up from the shore. And, of course, from burning fossil fuels.

Particulate matter generally gets evaluated for its effect on human health based on its diameter. Air quality rules for the United States tend to focus on PM2.5, matter that is about 1/20th the diameter of a human hair.

A large body of research has shown that the more particulate matter people breathe, the more likely they are to die, particularly if they’re older, says pediatrician Dr. Aaron Bernstein, interim director of the Center for Climate, Health and the Global Environment at Harvard University. Bernstein did not work on the Harvard study.

PM2.5 can cause heart attacks, strokes and lung cancer and there’s strong evidence now that it can promote the development of Type II diabetes, contribute to mental health problems and affect a developing fetus, Bernstein adds. There's also increasing evidence that it can damage the brain and that it could contribute to cases of dementia and autism.

“The bottom line is particulate matter is just generically really bad for us. And in many places in the world, including the United States, the major source is from burning fossil fuels. In other places, where people are using indoor cookstoves, for instance, and burning wood or dung or other things in their homes, that's a major source.”

Dr. Aaron Bernstein, Center for Climate, Health and the Global Environment, Harvard University

“The bottom line is particulate matter is just generically really bad for us,” Bernstein says. “And in many places in the world, including the United States, the major source is from burning fossil fuels. In other places, where people are using indoor cookstoves, for instance, and burning wood or dung or other things in their homes, that's a major source.”

Now, scientists have noted a link between the likelihood of a COVID-19 patient dying from the disease and the patient’s exposure to particulate matter air pollution.

“In the last week, we've had evidence specifically on COVID-19 in the United States showing that…if you've lived in a place with overall worse air pollution, the death rate increases by 15% for every one microgram per meter cubed of air particulate matter air pollution,” Bernstein says.

To put that in context, Bernstein says, in Boston, where he lives, particulate matter levels will rise to 15 or 20 micrograms per cubed meter on a bad day. In many places in the United States, levels can rise to 30. So, data showing that a one-microgram-per-meter-cubed difference over long periods leads to a 15% increase in the death rate from COVID-19 is significant.

The researchers controlled for other factors such as wealth, baseline health levels, access to health care and host of other things, Bernstein points out, and, even accounting for all those things, they still found that small differences in exposure to air pollution can affect whether a patient will die of COVID-19 or not.

All told, particulate matter kills between 7 and 10 million people every year around the world, mostly in Asia. “It’s in the top 10 causes of death, maybe in the top five, by some estimates,” Bernstein says.

In the US, between 100,000 to 200,000 people die every year from exposure to particulate matter, but that death toll is not distributed evenly across the population.

“If you're poor, if you're African American, if you're Latino, your odds of getting sick and dying from particular matter are much higher than other folks,” Bernstein says. “And we know, of course, that, short of death, there are a lot of bad things that happen to people from air pollution."

“As a pediatrician, I know that air pollution can be a major risk for everything from ear infections to pneumonia,” he adds. In addition, particulate matter can both cause and exacerbate asthma in children and adults.

Like other scientists and health professionals, Bernstein also notes a direct link between air pollution in the form of particulate matter and climate change. Air pollution from burning fossil fuels contributes to an enormous number of deaths and fossil fuels are also responsible for about 70% of global carbon emissions. So, reducing or eliminating fossil fuels is a win-win.

Related: Mutual aid groups respond to double threat of coronavirus and climate change

“If we get off fossil fuels, we get rid of huge burdens of disease right now,” Bernstein says. “I think it’s critical [that] we don't wait for months or years. When you stop burning coal in a power plant and convert it to renewables, the change in health happens right now. … And, of course, that means there are also less carbon emissions, which protects the climate moving forward."

“I've been saying for the past several weeks that climate actions are pandemic prevention actions, and a lot of folks, I think understandably, get rankled by that,” he continues. “‘How can you be talking about climate change when people are dying of an infectious disease right now?’ And my answer to that is pretty easy: …[W]e know now that our health, the population health of people in this country, is a huge factor in how we deal with something like COVID-19.”

During the pandemic, US President Donald Trump and the US Environmental Protection Agency have continued to loosen rules controlling air pollution of all kinds, heightening concerns among public health professionals. Even before the latest round of regulation, air pollution levels in the US rose in the last three years, for the first time in decades, Bernstein notes.

“So, we already have this uptick in air pollution; now we have evidence that air pollution may be more risky; and we potentially have an EPA that's saying, ‘Let's not pay as much attention to air pollution.’ That would certainly give me pause, particularly for those folks in our communities that are most at risk,” Bernstein says.

As for how to deal with the present crisis, Bernstein advises parents and children to continue to pay attention to the hygiene and distance guidelines put out by health experts because even if your own risk is low, your actions help protect the people most at risk.

“There aren't a lot of silver linings in this mess, but one of them could be that we cultivate a cohort of children who really get that we do things not always for ourselves,” Bernstein says. “That sometimes the right thing to do, which may not be something that we would do for ourselves otherwise, is important to do because it saves lives [and] keeps the people in our communities healthy — that we make decisions that matter beyond ourselves." 

Related: Coronavirus is changing how people think about fighting climate change

He adds: “There’s been no experience in recent memory that has made it clearer than this one that our health is absolutely tied to the communities we live in and to the living world and that we simply must move forward on that basis if we want to make sure that our children grow up to have the opportunities and health that so many of us have enjoyed.”

This article is based on an interview by Steve Curwood that aired on Living on Earth from PRX.