Pollution hurts health, may pose pandemic risk

Medical groups are increasingly addressing the relationship between the climate and health, and how predominantly lower-income, Black, or Hispanic/Latino communities have taken the brunt of pollution's impact.

For decades, research has shown that air pollution poses risk for respiratory and cardiovascular health, and particularly for older and other vulnerable populations. Now four out of 10 Americans, more than 135 million, live in a U.S. county with unhealthy levels of ozone or particle pollution, according to the American Lung Association's most recent “State of the Air” report, published in April. While the federal Clean Air Act has made some progress, the report noted that air monitoring indicates that the changing climate, with extreme heat and wildfires, is “making it harder to protect human health.”

Medical groups are increasingly adding their voice. ACP has regularly highlighted the relationship between the climate and health, including in a 2016 position paper published in Annals of Internal Medicine. And in a recent policy statement, published Dec. 8, 2020, in Circulation, the American Heart Association detailed how predominantly lower-income, Black, or Hispanic/Latino communities have taken the brunt of pollution's impact, as those residents are more likely to live or work near high-traffic or other polluted areas. The authors further wrote that “continued exposure to air pollution could explain in part the continued disproportionate CVD [cardiovascular disease] burden in disadvantaged communities.”

In addition, the recent American Lung Association (ALA) report found that people of color were 61% more likely than White Americans to live in a county with a failing grade related to unhealthy air.

It's important for physicians to understand their patients' socioeconomic circumstances, and this is another reason why, said Joel Kaufman, MD, MPH, FACP, lead author of the recent AHA policy statement and a professor of internal medicine and environmental health at the University of Washington in Seattle.

“You have to be concerned that your patients who are at the most disadvantaged for other reasons may in fact also be at the most disadvantaged with regard to their environmental exposures and pollution exposures,” he said. “Because they may live in an area that's more impacted by pollution and they probably have less access to the things that can improve their environment, like air filtration or air conditioning.”


The ALA report, which reflects air monitoring data from 2017 through 2019, found that nearly 15 million fewer U.S. residents are breathing unhealthy air compared with the prior year's report, primarily due to improvements in ozone pollution. But climate forces are working against those encouraging trends, the authors wrote. Heat plays a role in boosting unhealthy levels of ozone, a powerful lung irritant. Wildfires generate more particle pollution.

Long-term exposure to fine particles less than 2.5 micrometers, as well as ozone, boosts the likelihood that older adults will be hospitalized with respiratory and cardiovascular conditions, including heart attack and stroke, according to a recent study. The research, based on an analysis of the hospitalization records for more than 63 million Medicare patients, was published April 20 in Circulation.

And it's not just the heart and the lungs that can be damaged. An analysis of dermatology visits in San Francisco during and shortly after the 2018 Camp Fire, which was started by a faulty electric transmission line and exacerbated by drought, found that eczema symptoms increased among both adults and children, most of whom had not previously been diagnosed. The study was published online April 21 in JAMA Dermatology.

While notably unhealthy air has long been an issue elsewhere internationally, the recent wildfires along the West Coast have made the pollution risk literally more visible in the U.S., said Peter Orris, MD, MPH, FACP, professor and chief of occupational and environmental medicine at the University of Illinois Hospital and Health Sciences System in Chicago. “We had a taste in the U.S. of those kinds of levels of particulate and other pollutions,” he said.

Ashley E. McClure, MD, FACP, a general internist in Oakland, Calif., was on maternity leave with her daughter in 2018 and watched as the Camp Fire ravaged Paradise, Calif., and nearby communities, along with smothering the Bay Area in smoke.

“I couldn't safely go outside with my daughter for 13 days,” said Dr. McClure, a general internist in Oakland, Calif., who later cofounded the nonprofit advocacy coalition Climate Health Now. “I felt like I was seeing the future.”

More recently, the pandemic has revealed an association between long-term exposure to fine particles and a higher likelihood of contracting COVID-19, including developing severe disease, said ACP Resident/Fellow Member Stephen Andrew Mein, MD, a hospitalist at Boston's Beth Israel Deaconess Medical Center and lead author of a related commentary published online April 6 in the Annals of the American Thoracic Society.

The commentary, which looked at studies exploring the association, noted that the precise mechanism is not fully understood. There may be several underlying causes, Dr. Mein said. For instance, studies have already shown that pollution can impair the immune system and thus the body's ability to fight off infection, he said.

Moreover, long-term exposure to pollution has been linked to some diseases, including cardiovascular and metabolic conditions such as diabetes, he said. “A lot of those same comorbidities have been associated with worse outcomes for COVID.”

Personal protective measures

When relevant, physicians should educate patients about the role that air pollution can play in their health, said Emily Senay, MD, MPH, an assistant professor of environmental medicine and public health at Icahn School of Medicine at Mt. Sinai in New York City. She helped author a March opinion piece in Annals of Internal Medicine that looked at ways to discuss climate change with patients. “Climate is as linked to health as is a high-fat diet to cholesterol,” she said.

Take an elderly patient with heart disease who prefers to walk in the evening and has noticed that he feels a bit more chest pain around rush hour, Dr. Senay said. The physician can explain that particulate matter air pollution is caused by burning fossil fuels, before going on to advise, “There are times of the day when air pollution is worse, especially during the evening rush. That could be one reason why you're seeing a worsening chest pain. Why don't we adjust when you're taking your walk?”

Nitin Damle, MD, MS, MACP, a Rhode Island general internist and a former ACP President, will talk to his patients with respiratory and other at-risk conditions about monitoring daily air quality. He's happy to discuss pollution's link to the world's climate if the patient seems receptive. Otherwise, he steers clear. “The exam room is a place where patients should feel like they're comfortable with their physician, and not have to get into the politics of certain issues,” he said.

Helping patients better protect themselves can be tricky, as the biggest risk factor likely can't be addressed, Dr. Orris pointed out. “Telling me I need to be in a community with lower levels of pollution, I feel like I really can't do much about that.”

But patients, and particularly those with underlying cardiovascular or respiratory conditions, can be advised to wear a mask, ideally an N95, if they must venture outside during poor air-quality days, Dr. Orris said. They can be educated about the importance of changing their air filters regularly if they have air conditioning in their homes, he said.

In a scientific statement published in the same Dec. 8, 2020, Circulation issue as its policy statement, the American Heart Association detailed the latest research on air filtration, mask wearing, and behavioral changes among other personal protective measures that individuals can adopt. Some potential behavioral strategies include avoiding commuting during peak pollution times and closing a vehicle's windows when driving through polluted areas. Research also indicates that avoiding exercise within 400 meters of highways or other major roads “could potentially reduce exposure” to air pollution, especially for high-risk individuals, the authors wrote.

But given that some patients can't alter where or when they exercise, that should not be used as an excuse to punt on regular physical activity, Dr. Kaufman said. “Unless it's a hazardous-for-everybody air pollution day, or unless you're in an extremely high-risk group, you shouldn't forgo exercise to avoid air pollution exposures.”

Physicians should more frequently leverage their influence as trusted members of society to advocate for climate action, Dr. McClure said. The group she cofounded, Climate Health Now, was launched in 2019 and includes a coalition of California health professionals working to reduce use of fossil fuels in favor of renewable energy. Another physician-centered group, the Medical Society Consortium on Climate and Health, has 33 member societies, including ACP, and works to inform the public and policymakers about climate change. Robert M. McLean, MD, MACP, ACP's President for 2019-2020, is on the Consortium's steering committee, and current ACP President George M. Abraham, MD, MPH, FACP, serves as ACP's official liaison.

While Dr. Damle strives to avoid controversial climate-related discussions in the exam room, he's spoken out more in recent years about the health impact of a changing climate, including during his term as ACP President in 2016-2017. Since 2015, he estimates that he's given more than 35 presentations, primarily to medical groups.

In addition, physicians can work not just through medical organizations but also advocate through their local communities and educate legislators, both locally and at the federal level, Dr. Damle said. “When you're not in the exam room,” he said, “you really should be an advocate for speaking about climate change and how it's affecting the earth.”