Member Spotlight

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Dr. Özkaynak has over 40 years of experience in performing research in the areas of environmental exposure sciences and human health and risk assessment. He holds a Ph.D. in Mathematical Physics from Harvard University and a Master of Science Degree in Environmental Health from Harvard School of Public Health. Specifically, Dr. Özkaynak is an internationally recognized expert on the topics of modeling real-world human exposures to air and multimedia pollutants, air pollution epidemiology and conducting environmental impact studies that support community health and risk evaluations. Dr. Özkaynak has over 100 peer-reviewed publications covering diverse topics within the fields of exposure sciences (air and multimedia exposure modeling and assessment), air pollution epidemiology (acute and chronic health effects of air pollution) and human health risk assessments conducted for various agents and chemicals released from air and multimedia sources. Dr. Özkaynak served as the President of the International Society of Exposure Sciences (ISES) in 2001. Presently he is an Associate Editor of the Journal of Environmental Health Perspectives (EHP) and a part-time consultant to an EPA contractor.


Dr. Özkaynak spent most of his early career at Harvard University School of Public Health as a Lecturer before joining the US Environmental Protection Agency’s (EPA’s) National Exposure Research Laboratory (NERL) in 1998. Prior to joining EPA, Dr. Özkaynak was a Lecturer at the Department of Environmental Health of Harvard School of Public Health in Boston. During his ~20 year career at Harvard his research included: managing a first of its kind large multiyear multidisciplinary study on assessment of particle exposures, toxicity and health effects (long before EPA initiated its PM Centers); directing a large-scale environmental epidemiology study in Russia; managing the Kanawha Valley Health Study on air toxics exposures and health effects in WV; contributing to the NHEXAS study on exposures to criteria pollutants; participating in a multiyear study sponsored by GRI on NO2, and; serving as the co-PI for the large EPA study on measurement of personal exposures to fine particles (i.e., the  PTEAMS study).


As the Science Lead for the human exposure modeling program of EPA/NERL (1998-2004) he initiated and led the development of Agency’s premier mechanistic human exposure model (i.e. the “SHEDS” or the Stochastic Human Exposure and Dose Simulation model), which utilizes probabilistic techniques to quantify both the variability and uncertainty in the exposure model predictions for a wide range of pollutants. In addition, he oversaw the development of higher-tier source to dose population exposure models under a long-term university partnership program. This program included several researchers from LBL, Stanford university and EOHSI.  In 2004 Dr. Özkaynak became a Senior Scientist (ST) at EPA/ORD/NERL’s Director’s Office charged with conducting and sponsoring integrative and multidisciplinary research. As part of improving the underlying science of integrative research, Dr. Özkaynak initiated a university cooperative agreement program with Rutgers, Emory and University of Washington in order to evaluate the utility of using higher-tier exposure models in alternative epidemiological model applications and in different types of geographical settings. He encouraged broader communication of the study results by arranging for the publication of key study findings within a special issue of the JESEE. Following this activity, he continued performing integrative multidisciplinary research by developing a novel moderate-tier exposure modeling tool, for the purposes of conducting more efficient human source-to-concentration-to-exposure-to-effects modeling for large numbers of multimedia chemicals of concern. Specifically, he conceived and implemented the development of a model (SHEDS-HT) for rapid and high throughput evaluation of thousands of consumer product chemicals of interest.


In addition to his contributions to the exposure sciences, exposure modeling and air pollution epidemiology fields, over the past decade, Dr. Özkaynak contributed to the development approaches and models for estimating incidental soil and dust ingestion rates by children and adults. Soil and dust ingestion rates are exposure factors that are highly important to both multimedia human health risk assessment and superfund clean-up/risk management activities. He continued working on this important topic even after his retirement from EPA in late 2014.  Throughout his career Dr. Özkaynak advised or mentored numerous doctoral students, post-docs and many junior scientists, staff or faculty members from several universities, EPA and other governmental organizations. Throughout his over 40-year career in exposure sciences, Dr. Özkaynak collaborated with numerous international institutions (e.g., in Taiwan, Canada, Russia, South Africa and various countries in the EU, Middle East and in Latin America). He has organized domestic and international symposia and chaired/co-chaired or participated in numerous domestic and international workgroups, including co-chairing the chemical exposures workgroup of the National Children’s Study (NCS). He also represented the US government in the EU/US/Canada transatlantic environmental exposure harmonization activities, WHO workgroups and the OECD’s workshop on children’s exposures. 

Past Spotlights


Judy LaKind

Crystal Romeo Upperman

Sonja Sax

Brian Curwin

Anne M. Riederer


Christopher Simpson

Yuri Bruinen De Bruin

Lisa Baxter

Erin Haynes

Lesliam Quirós-Alcalá


Rick Peltier

Paloma Beamer

Zhi-Hua (Tina) Fan

Shahid Parvez

Sung Roul Kim

Elizabeth Boyle

Markey Johnson

Natalie von Gotz


Tom McKone

Antonia Calafat

Donghai Liang

Lisa Melnyk



Mary Kay O’Rourke 

Paul T.J. Scheepers

Nicolle S. Tulve