University of Michigan environmental epidemiologist uncovers hidden health risks in the environment
Sung Kyun Park studies how PFAS, lead and other environmental toxicants affect human health, from reproductive disorders to Alzheimer’s disease and dementia
By Bob Cunningham
Sung Kyun Park’s interest in public health began with instant noodles.
Growing up in Seoul, Park studied food science and technology as an undergraduate, focusing on the chemistry and engineering behind the foods found on grocery store shelves.
During his senior year, however, a national controversy changed the direction of his career.
Reports emerged suggesting that eating cup ramyeon—a beloved South Korean comfort food packaged in Styrofoam containers—might affect male fertility. Scientists worried that styrene, a chemical compound in the foam, could leach into the noodles when exposed to hot water and oily broth, potentially disrupting hormone levels and reducing sperm quality.
The uproar fascinated Park. He became less interested in how food was made and more curious about how it affected human health.
“I found this phenomenon interesting and became more interested in the health effects of food than in food manufacturing processes,” Park said. “This experience led me to pursue public health and study environmental health.”
Park earned his bachelor’s degree in Food Science and Technology and master’s degree in Environmental Health, both from Seoul National University, before completing his doctorate in Environmental Epidemiology at the Harvard T.H. Chan School of Public Health.
It is also deeply rewarding to hear from former students that, many years later, they still go back to my lecture slides and codes in their work. In fact, my students have taught me how to become a better teacher, so they deserve to share this award.”
Before coming to the United States, he worked as an occupational epidemiologist at South Korea’s Wonjin Institute for Occupational and Environmental Health, an organization founded using settlement funds from workers exposed to carbon disulfide in one of the country’s worst industrial disasters. There, Park credits institute director Rokho Kim with inspiring him to pursue a career in environmental epidemiology.
Park joined the University of Michigan School of Public Health in 2006 as a postdoctoral fellow in Environmental Health Sciences and has remained at the university ever since, becoming a faculty member in Epidemiology in 2010. Today, he is a professor of Epidemiology and Environmental Health Sciences, studying how everyday exposures—from PFAS “forever chemicals” to heavy metals like lead—affect human health over a lifetime.
In spring 2026, Park’s dedication to teaching earned him the School of Public Health’s Excellence in Teaching Award, a recognition he calls the most meaningful of his career.
“I have been teaching here for almost 20 years, and I consider myself as an example of learning through failure,” Park said. “My teaching evaluations were not very strong early in my career, and as an international faculty member, language was an additional barrier. However, students’ evaluations and feedback have been essential to my growth.”
He said he has enjoyed seeing students grow while taking his courses.
“It is also deeply rewarding to hear from former students that, many years later, they still go back to my lecture slides and codes in their work,” Park said. “In fact, my students have taught me how to become a better teacher, so they deserve to share this award.”
In this Q&A, Park discusses his research on chemical exposures, his ongoing study linking environmental toxicants to Alzheimer’s disease and dementia, and practical steps people can take to reduce their own exposure to harmful pollutants.
What parts of public health are most interesting for you?
What interests me most about public health is how the environment—what we breathe, drink, eat and use in everyday life—influences our bodies and shapes who we are, including our health. The environment affects not only me but also my family, friends and everyone in my community. It is important to understand how specific environmental factors are distributed and whether differences in those distributions ultimately affect population health.
I also find public health fascinating because it provides the core scientific foundation for responding to population-level health issues. For example, I was unfamiliar with per- and polyfluoroalkyl substances (PFAS), often called “forever chemicals,” until the 2017 PFAS contamination in Kent County, Michigan—in the Grand Rapids area—where Wolverine Wide World, a leather footwear manufacturer, contaminated drinking water with PFAS. Since then, these chemicals have become a research priority for me.
What drew you to epidemiology?
The most fascinating feature of epidemiology is its ability to investigate our questions and test our hypotheses using observational data from populations. I will never forget the paper that made me fall in love with epidemiology written by Neils Skakkebaek and colleagues, “Evidence for Decreasing Quality of Semen during Past 50 Years,” published in the British Medical Journal in 1992. The paper reviewed studies from 1938 to 1991 and showed a clear decline in sperm count over that period. During the same time, rapid industrial development led to increased population-wide exposure to environmental toxicants. Epidemiology uses such population data to assess whether an exposure causes a health effect. How fascinating!
What is your main area of research?
I use epidemiologic causal inference methods and environmental exposure assessment to examine associations between environmental toxicants—including PFAS, heavy metals, chemicals in personal care products, and air pollutants—and aging-related health outcomes. I also use the exposome framework, which refers to the totality of exposures over a person’s lifetime. Rather than examining only specific exposures with known biological effects, we analyze hundreds to thousands of environmental factors to identify which ones are associated with health outcomes. This data-driven approach is important because toxicological data exists for only a small fraction of the chemicals used in everyday life.
Your work often focuses on pollutant mixtures rather than single exposures. Why is that important?
As people are exposed to multiple toxicants simultaneously, my research interests have evolved from studying individual pollutants to investigating multiple pollutants and their combined effects. For example, an individual may be exposed to particulate matter through the air while also being exposed to lead and PFAS through drinking water. Estimating the combined effects of these exposures is therefore important for understanding their true impact on human health and informing prevention strategies. This work has several challenges, including measuring exposures accurately, disentangling highly correlated exposures, and developing statistical methods that can capture individual, combined and interactive effects.
What are you learning about environmental exposures and brain aging through your dementia research?
Let me start with lead. Lead exposure in the United States has declined significantly over the past several decades—one of the major public health achievements of the 20th century. However, people born before 1980, including baby boomers and Generation X, may have been exposed to high lead levels from leaded gasoline and lead-based paint. In adults, bones hold approximately 90-95% of the body’s total lead burden, sometimes for several decades. As bone density declines with aging, this stored lead can be released back into circulation. Our team was the first to provide empirical evidence that cumulative lead exposure is associated with a higher risk of Alzheimer’s disease, and all-cause dementia. Our next steps are to determine which populations are most susceptible to the neurodegenerative effects of environmental chemicals and to understand the biological mechanisms linking these exposures to brain aging.
What practical steps can people take to reduce harmful exposures?
I recommend several strategies. For example, people can use a water filter if lead in their drinking water is a concern or wear an N95 mask when air quality is poor, such as during wildfire smoke events. It’s also important to be aware of common exposure sources—diet and everyday consumer products are major sources of PFAS exposure, which may be present in grease-resistant food wrappers, waterproof fabrics and some cosmetics. Although it’s impossible to avoid all exposures, recognizing these sources can help us make informed choices. Ultimately, effective prevention should focus on population-level strategies, including stronger environmental policies, adequate resource allocation and public education.
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Destiny Cook
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