Researchers issue warning over escalating threat to public health: 'We're talking about millions of people affected'

Studies have shown that air pollution puts people at risk of heart issues and early death — and Harvard researchers are highlighting this connection.

What's happening?

An article from the Harvard T.H. Chan School of Public Health reported that, while many people are aware that air pollution can affect their respiratory health, it's less known that it also affects their heart health. 

The Harvard Six Cities Study, released in 1993, showed a strong link between air pollution and an increased risk of mortality, particularly from lung cancer and heart disease. The study was led by Douglas Dockery, a Harvard emeritus professor.

As detailed in the recent article, Dockery initially believed the mortality risk was due to respiratory disease, not cardiovascular disease. He even thought there was an error in the coding. However, the study found that air-pollution-related deaths were linked to cardiovascular disease. 

Before this study, scientists did not fully understand the seriousness of air pollution. Since then, Harvard researchers have published numerous papers on the topic. 

While the Six Cities Study was criticized, many follow-up studies have confirmed its findings. 

For example, a 2001 study tracked heart attacks in Boston between 1995 and 1996. It found that heart attack risks increased when fine particulate matter was higher for two hours prior, as the recent article summarized. 

A 2024 study "found that chronic exposure to fine particulate pollution may increase seniors' risk of hospitalization for a variety of cardiovascular conditions, particularly ischemic heart disease, cerebrovascular disease, heart failure, and arrhythmia," per the article.

"The smaller the particles in air pollution, the worse they are for cardiovascular health, evidence shows. PM2.5 particles are considered the most dangerous."

PM2.5 primarily comes from cars, trucks, steel mills, and coal plants, the latter of which generates twice as much deadly fine particulate matter as other sources, according to the publication. Wildfires also produce PM2.5.

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Why is air pollution that affects heart health concerning?

Air pollution has contributed to a devastating number of deaths. According to a 2017 study by The Lancet, fine particulate matter contributed to about 4.2 million deaths worldwide in 2015, as the Harvard article detailed — and 2.4 million of those deaths were cardiovascular-related, compared to 863,000 from lung disease and 283,300 from lung cancer. 

"We're talking about millions of people affected," Dockery said in the recent Harvard article of the links between pollution and heart risks.

What's being done about air pollution's deadly effects?

There are several ways to protect yourself from air pollution, including using the Environmental Protection Agency's air quality monitoring tool (airnow.gov), wearing an N95 mask when air quality is poor, and using HEPA air filters or creating your own. 

However, Dockery said, "The key is really to improve outdoor air quality." 

Researchers suggest tackling air pollution at its source, such as using renewable energy sources like solar. 

Mary Rice, director of the Center for Climate, Health, and the Global Environment, believes that policies to reduce reliance on dirty energy sources will benefit both heart health and lung health. 

Research can also advance policies. The Six Cities Study led the way for stricter air quality standards in the U.S, and more still needs to be done.  

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