Dr. Chen is a senior environmental epidemiologist who focuses on perinatal and pediatric outcomes and a variety of exposures: lead, mercury, cadmium, DDT, isoflavones, flame retardants, perfluoroalkyl substances (PFAS), air pollution, and electronic waste recycling. He has established international studies to examine chemical mixture exposure from informal e-waste recycling in resource-poor communities and has raised awareness of the potential chemical toxicity to pregnant women and developing children; these efforts have impacted policy making and prevention. He has systematically investigated thyroid hormone disruption and developmental neurotoxicity in children from prenatal and postnatal exposure to polybrominated diphenyl ethers (PBDEs) and PFAS, using the Health Outcomes and Measures of the Environment (HOME) Study, a Cincinnati-based pregnancy and birth cohort with repeated childhood follow-ups.

Currently Dr. Chen is extending that investigation to organophosphate esters (OPEs) and replacement brominated flame retardants (RBFRs) with neuroimaging and with repeated neurobehavioral assessments till early adolescence. He is also investigating chemical mixture exposures and child neurobehavior using U.S. and Canadian birth cohorts. He is involved in and is curator of the Treatment of Lead-exposed Children (TLC) Study, a placebo-controlled multi-center randomized clinical trial at sites including Philadelphia, following its completion at the National Institute of Environmental Health Sciences (NIEHS). He is an Associate Editor of International Journal of Hygiene and Environmental Health and serves on the editorial review board of Environmental Health Perspectives. At Penn, he is Associate Director of the Integrative Health Sciences Facility Core (IHSFC) in the NIEHS-funded Center of Excellence in Environmental Toxicology (CEET). He is Co-Director of the NIEHS-funded Philadelphia Regional Center for Children's Environmental Health (PRCCEH). His work will further expand environmental epidemiologic research at the Perelman School of Medicine and the Children’s Hospital of Philadelphia.