An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Healthy Heart Toolkit and Research: Results

EPA researchers and partners are learning more about how people can better protect their cardiovascular health from air pollution.

A large and robust body of research has been published in peer-reviewed journal articles by EPA and EPA-funded scientists on the health effects of air pollution, including the heart, nervous and vascular systems.  

This research has shown that exposure to fine particle pollution, known as PM2.5, can impact heart disease. Particles are emitted year-round from motor vehicles, power plants, industries, and naturally from forest fires. PM also develops from chemical reactions in sunlight from vapor and gaseous pollutants.

For additional EPA reports, journal articles and presentations, visit the Science Inventory.

Highlighted Published Research



  • In an EPA study, researchers observed that long-term exposure to PM2.5 increased the number of small, cholesterol particles in the bloodstream of the individuals who underwent cardiac catheterization and therefore may make susceptible populations more prone to cardiovascular disease. The study is the first of its kind to describe these new cholesterol biomarkers that focus on size rather than total cholesterol in the blood. The results are published in the January 2019 article in the journal Environmental International. Exit


  • In an article in the North Carolina Medical Journal, researchers observe that air pollution’s cardiovascular effects pose an even larger public health burden than its respiratory effects. Yet, the authors note that only three percent of patients with heart disease discuss guidance to reduce exposure with a health professional as shown in a study by the Centers for Disease Prevention and Control (CDC). The researchers explain the sources, exposures, and health effects of air pollution and discuss the potential for intervention strategies in the health care system to help reduce individual and population exposure and the attendant risk from the cardiovascular effects of air pollution. Ambient Air Quality and Cardiovascular Health: Translation of Environmental Research for Public Health and Clinical CareExit
  • An article in the North Carolina Journal of Medicine provides information for public health and clinical care on air quality and cardiovascular health.  Ambient Air Quality and Cardiovascular Health. Exit
  • A study in the Journal of American Heart Association found smoke exposure to be associated with cardiovascular and cerebrovascular emergency department visits for all adults, particularly for those over aged 65 years for the 2015 California wildfire season. Cardiovascular and Cerebrovascular Emergency Department Visits Associated With Wildfire Smoke Exposure in California in 2015. Exit
  • A study published  in the Journal of the American Heart Association, looked for possible associations between daily maximum smoke density (low, medium, and dense) and over a million hospital Emergency Department (ED) visits in northern and central California, over a five-month period in 2015 at a ZIP code level of resolution. The study found a positive association between ED diagnoses for heart, brain, blood vessel, and respiratory disease relative to days without wildland fire smoke exposure.  Impacts were greatest on medium and dense smoke days, and among adults 65 years and older. The publication is a product of a multi-disciplinary collaboration between EPA researchers, the State of California Department of Public Health, and academic partners at the University of California, San Francisco. Open access journal articleExit


  • A large body of evidence has confirmed that fine particulate matter (PM2.5) is a major risk factor for cardiovascular disease. But what about ozone, another common air pollutant? Previous epidemiological studies suggest that there is a relationship between the air pollutant and cardiovascular health effects, but this work is inconclusive. In a  study in Environmental Health, EPA researchers investigated the ways in which ozone impacts the cardiovascular system and found that exposure altered several biological pathways associated with cardiovascular disease in coronary artery disease patients. The findings support the plausibility that ozone exposure can cause negative cardiovascular health effects in susceptible populations. Ozone exposure is associated with acute changes in inflammation, fibrinolysis, and endothelial cell function in coronary artery disease patientsExit
  • In an animal study in Cardiovascular Toxicology, findings suggest that ultrafine particle pollution may affect mitochondrial function important to regulating normal cardiac metabolism. Ultrafine Particulate Matter Increases Cardiac Ischemia/Reperfusion Injury via Mitochondrial Permeability Transition PoreExit
  • A study investigated the relationship between neighborhood-level factors and cardio-metabolic disease by using hierarchical clustering of data.  A novel approach for measuring residential socioeconomic factors associated with cardiovascular and metabolic healthExit published in the Journal of Exposure Science & Environmental Epidemiology.
  • In a study published in PLoS One, researchers from EPA and University of North Carolina in Chapel Hill, NC, used new molecular biology techniques to show that the colony of microorganisms (microbiota) living in the lungs is altered in burn patients with damaged airways from smoke inhalation. Not too long ago, the surface of the lung was considered to be sterile with no microorganisms. Now, studies indicate microbiota not only live in the lungs, but also play a role in their health. As a result, scientists are interested in learning what happens to the living colony when the airways are damaged such as by air pollutants.  Lungs damaged by smoke may change the balance of good microbes and harmful ones such as bacteria that lead to respiratory disease. These bacteria cannot be detected by conventional techniques such as cell culturing, but have been identified with the molecular techniques. Ongoing research will explore whether the same or similar changes in microbiota observed in severe smoke inhalation cases occurs in individuals who are exposed to high-pollution events or wildfires.   Alterations in airway microbiota in patients with PaO2/FiO2 ratio ≤ 300 after burn and inhalation injury.Exit
  • Do our genes make us more sensitive to air pollution? In a large study in PLoS One by EPA and Duke University, researchers identified several novel genes associated with coronary artery atherosclerosis in heart patients who have been exposed to traffic-related air pollution for a long time. Atherosclerosis results in plaque build-up in the arteries, which can lead to heart attacks and strokes. The research adds to the large body of evidence that shows the link between air pollution near roadways and cardiovascular disease. While other studies have looked at the gene-air pollution connection, this is the first to examine the entire genome and its potential to respond to emissions from traffic. A genome-wide trans-ethnic interaction study links the PIGR-FCAMR locus to coronary atherosclerosis via interactions between genetic variants and residential exposure to traffic.Exit
  • EPA scientists developed a Community Health Vulnerability Index that can be used to help identify communities at higher health risk from wildfire smoke. Smoke inhalation is a health threat, especially for people with lung or heart disease, diabetes and high blood pressure as well as older adults, and people in communities with poverty, unemployment and other indicators of social stress. State and local governments can use the tool, in combination with air quality forecasting models, to “map” areas where vulnerable populations are at higher risk from poor air quality, including areas prone to wildfires. Health officials can learn where to focus public health strategies to protect individuals living in areas where air quality is impaired, either by wildfire smoke or other sources of pollution.  The study was published in Environmental Science & Technology.  Community vulnerability to health impacts of wildland fire smoke exposure.Exit

  • EPA researchers applied a novel hierarchical clustering technique to identify residential areas with similar characteristics using demographic data from the US Census. An existing group of individuals with a previous cardiac catheterization already living in those areas was then examined for their cardio-metabolic health. After controlling for individual risk factors, the researchers found that individuals living in more disadvantaged areas are more likely to be obese and have diabetes, congestive heart failure, and hypertension compared with those living in the most-advantaged area. Future research will focus on whether living in disadvantaged areas confers a greater susceptibility to the adverse effects of air pollution. In addition, public health officials can use this information to target assistance for communities that are susceptible to cardiovascular and metabolic disorders due to their residential characteristics.  The study was published in Journal of Exposure Science and Environmental Epidemiology. A novel approach for measuring residential socioeconomic factors associated with cardiovascular and metabolic health.Exit


  • A causal link between fine particulate matter (PM2.5) and cardiac death is well established, but what are the biological steps to adverse cardiopulmonary outcomes? And what makes certain individuals susceptible to PM2.5 ‘s adverse clinical effects? An article describes the physiological changes likely to occur in people with cardiovascular disease that can lead to cardiac arrest or sudden death with high levels of PM2.5. The article also explains the importance of direct and indirect health interventions to reduce the impacts of air pollution on heart health. Proposed Pathophysiologic Framework to Explain Some Excess Cardiovascular Death Associated with Ambient Air Particle Pollution: Insights for Public Health TranslationExit
  • Researchers from the Harvard Clean Air Research Center, funded by EPA, evaluated biomarkers of oxidative stress in blood and urine and their association to short-term exposure to fine particulate matter (PM2.5), black carbon, and other air pollutants. Biomarkers in blood were positively associated with PM2.5 and black carbon concentrations, and biomarkers in urine were positively associated with fine particulate matter and sulfate. These associations were stronger for participants with diabetes. Additional research is needed to fully understand the observed link. A study published in Journal of American Heart Association, describes the study. Short‐Term Exposure to Air Pollution and Biomarkers of Oxidative Stress: The Framingham Heart Study.Exit


Top of Page