P. Barry Ryan, PhD, MS

Research Program

Cancer Prevention and Control
Phone Number

404-727-3826
Email Address

bryan@sph.emory.edu

Biography

P. Barry Ryan, PhD, MS, holds joint appointments as a professor in the Department of Environmental Health at Rollins School of Public Health and in the Department of Chemistry at Emory University. He is a member of the Cancer Prevention and Control Research Program at Winship Cancer Institute.

Dr. Ryan has worked with the U.S. Environmental Protection Agency, serving on the Board of Scientific Counselors for the EPA's Office of Research and Development (2006-2010) and as an ad hoc member of the EPA's Science Advisory Panel (2004-2006) and Human Subjects Review Board (2007).

Education

A graduate of the University of Massachusetts, Dr. Ryan received a master's degree from the University of Chicago and a PhD from Wesleyan University.

Titles & Roles

Professor, Department of Environmental Health

Rollins School of Public Health of Emory University
Professor, Department of Chemistry

Emory University

Professional Memberships

Dr. Ryan is a member of the International Society of Exposure Science.

Research

Dr. Ryan's research focus includes environmental exposure assessment and the impact it has upon human health. Numerous environmental contaminants are known human carcinogens. His team studies exposures to such compounds and the likely health outcomes. He began his work over 30 years ago with an initial focus on air pollution exposures.

He is currently collaborating with Winship investigators to study exposure to volatile organic compounds and its relationship to Non-Hodgkin lymphoma.

Publications

Title/Journal	Authors	Publication Date
Prenatal exposure to persistent organic pollutants and associations with child behavior problems at 1-5 years. Environmental pollution (Barking, Essex : 1987)	SM Eick, KE Ortlund, DB Barr, AL Dunlop, D Liang, EJ Corwin, PB Ryan, S Friedman, M Buhr, P Panuwet, PE D'Souza, V Yakimavets, GE Lee, A Huels, N Sehgal, Y Tan, PA Brennan	05/15/2025
Housing characteristics, dietary patterns, and sociodemographic characteristics as predictors of persistent organic pollutant exposure among African American pregnant women in Atlanta. Environmental research	K Ortlund, M Chandler, AL Dunlop, DB Barr, PB Ryan, D Liang, PA Brennan, M Buhr, EJ Corwin, P Panuwet, GE Lee, J Eatman, Y Tan, N Sehgal, SM Eick	05/01/2025
Impact of prenatal phthalate exposure on newborn metabolome and infant neurodevelopment. Nature communications	SS Hoffman, Z Tang, A Dunlop, PA Brennan, T Huynh, SM Eick, DB Barr, B Rushing, SL McRitchie, S Sumner, KR Taibl, Y Tan, P Panuwet, GE Lee, J Eatman, EJ Corwin, PB Ryan, DP Jones, D Liang	04/02/2025
A Prospective Analysis of Per- and Polyfluoroalkyl Substances from Early Pregnancy to Delivery in the Atlanta African American Maternal-Child Cohort. Environmental health perspectives	Y Tan, SM Eick, AL Dunlop, DB Barr, KR Taibl, K Steenland, K Kannan, M Robinson, CJ Chang, P Panuwet, V Yakimavets, CJ Marsit, PB Ryan, D Liang	11/01/2024
Maternal symptoms of depression and anxiety as modifiers of the relationship between prenatal phthalate exposure and infant neurodevelopment in the Atlanta African American maternal-child cohort. Brain, behavior, & immunity - health	K Springer, JA Eatman, PA Brennan, AL Dunlop, DB Barr, P Panuwet, PB Ryan, E Corwin, KR Taibl, Y Tan, SS Hoffman, D Liang, SM Eick	10/01/2024
Association of per- and polyfluoroalkyl substances with the antioxidant bilirubin across pregnancy. Free radical biology & medicine	KR Taibl, AL Dunlop, MR Smith, DI Walker, PB Ryan, P Panuwet, EJ Corwin, K Kannan, DP Jones, CJ Marsit, Y Tan, D Liang, SM Eick, DB Barr	10/01/2024
Prenatal exposure to persistent and non-persistent chemical mixtures and associations with adverse birth outcomes in the Atlanta African American Maternal-Child Cohort. Journal of exposure science & environmental epidemiology	SM Eick, Y Tan, KR Taibl, P Barry Ryan, DB Barr, A Hüls, JA Eatman, P Panuwet, PE D'Souza, V Yakimavets, GE Lee, PA Brennan, EJ Corwin, AL Dunlop, D Liang	07/01/2024
Corrigendum to "Exposure to phthalate metabolites, bisphenol A, and psychosocial stress mixtures and pregnancy outcomes in the Atlanta African American maternal-child cohort" [Environ. Res. 233, 15 September 2023, 116464]. Environmental research	JA Eatman, AL Dunlop, DB Barr, EJ Corwin, CC Hill, PA Brennan, PB Ryan, P Panuwet, KR Taibl, Y Tan, D Liang, SM Eick	06/15/2024
Prenatal exposure to per- and polyfluoroalkyl substances (PFAS) and associations with hypertensive disorders of pregnancy in the Atlanta African American Maternal-Child cohort. Chemosphere	M Thompson, JA Eatman, AL Dunlop, DB Barr, K Kannan, EJ Corwin, PB Ryan, P Panuwet, V Yakimavets, KR Taibl, Y Tan, D Liang, SM Eick	06/01/2024
Phthalate exposure increases interferon-γ during pregnancy: The Atlanta African American Maternal-Child Cohort. The Science of the total environment	KR Taibl, AL Dunlop, DB Barr, PB Ryan, P Panuwet, EJ Corwin, JA Eatman, Y Tan, D Liang, SM Eick	03/15/2024
Metabolic Perturbations Associated with an Exposure Mixture of Per- and Polyfluoroalkyl Substances in the Atlanta African American Maternal-Child Cohort. Environmental science & technology	D Liang, KR Taibl, AL Dunlop, DB Barr, PB Ryan, T Everson, A Huels, Y Tan, P Panuwet, K Kannan, C Marsit, DP Jones, SM Eick	10/31/2023
Exposure to phthalate metabolites, bisphenol A, and psychosocial stress mixtures and pregnancy outcomes in the Atlanta African American maternal-child cohort. Environmental research	JA Eatman, AL Dunlop, DB Barr, EJ Corwin, CC Hill, PA Brennan, PB Ryan, P Panuwet, KR Taibl, Y Tan, D Liang, SM Eick	09/15/2023
Association between a Mixture of Per- and Polyfluoroalkyl Substances (PFAS) and Inflammatory Biomarkers in the Atlanta African American Maternal-Child Cohort. Environmental science & technology	Y Tan, KR Taibl, AL Dunlop, DB Barr, P Panuwet, V Yakimavets, K Kannan, EJ Corwin, PB Ryan, JA Eatman, D Liang, SM Eick	09/12/2023
Newborn metabolomic signatures of maternal per- and polyfluoroalkyl substance exposure and reduced length of gestation. Nature communications	KR Taibl, AL Dunlop, DB Barr, YY Li, SM Eick, K Kannan, PB Ryan, M Schroder, B Rushing, T Fennell, CJ Chang, Y Tan, CJ Marsit, DP Jones, D Liang	05/30/2023
Pregnancy-related hemodynamic biomarkers in relation to trimester-specific maternal per - and polyfluoroalkyl substances exposures and adverse birth outcomes. Environmental pollution (Barking, Essex : 1987)	KR Taibl, D Liang, AL Dunlop, DB Barr, MR Smith, K Steenland, Y Tan, PB Ryan, P Panuwet, T Everson, CJ Marsit, K Kannan, DP Jones, SM Eick	04/15/2023
Metabolome-wide association study of the relationship between chlorpyrifos exposure and first trimester serum metabolite levels in pregnant Thai farmworkers. Environmental research	D Liang, J Batross, N Fiedler, T Prapamontol, P Suttiwan, P Panuwet, W Naksen, BO Baumert, V Yakimavets, Y Tan, P D'Souza, A Mangklabruks, S Sittiwang, K Kaewthit, K Kohsuwan, N Promkam, S Pingwong, PB Ryan, DB Barr	12/01/2022
Assessment of metabolic perturbations associated with exposure to phthalates among pregnant African American women. The Science of the total environment	X Zhang, DB Barr, AL Dunlop, P Panuwet, JA Sarnat, GE Lee, Y Tan, EJ Corwin, DP Jones, PB Ryan, D Liang	04/20/2022
Investigation of Prenatal Pesticide Exposure and Neurodevelopmental Deficits in Northern Thailand: Protocol for a Longitudinal Birth Cohort Study. JMIR research protocols	BO Baumert, N Fiedler, T Prapamontol, P Suttiwan, W Naksen, P Panuwet, S Sittiwang, C Dokjunyam, MM Smarr, CJ Marsit, PB Ryan, W Siriwong, MG Robson, DB Barr	02/07/2022
Per- and polyfluoroalkyl substance (PFAS) exposure, maternal metabolomic perturbation, and fetal growth in African American women: A meet-in-the-middle approach. Environment international	CJ Chang, DB Barr, PB Ryan, P Panuwet, MM Smarr, K Liu, K Kannan, V Yakimavets, Y Tan, V Ly, CJ Marsit, DP Jones, EJ Corwin, AL Dunlop, D Liang	01/01/2022
High-resolution metabolomics of exposure to tobacco smoke during pregnancy and adverse birth outcomes in the Atlanta African American maternal-child cohort. Environmental pollution (Barking, Essex : 1987)	Y Tan, DB Barr, PB Ryan, V Fedirko, JA Sarnat, AJ Gaskins, CJ Chang, Z Tang, CJ Marsit, EJ Corwin, DP Jones, AL Dunlop, D Liang	01/01/2022
Review: Evolution of evidence on PFOA and health following the assessments of the C8 Science Panel. Environment international	K Steenland, T Fletcher, CR Stein, SM Bartell, L Darrow, MJ Lopez-Espinosa, P Barry Ryan, DA Savitz	12/01/2020
LC-MS Quantification of Malondialdehyde-Dansylhydrazine Derivatives in Urine and Serum Samples. Journal of analytical toxicology	K Kartavenka, P Panuwet, V Yakimavets, C Jaikang, K Thipubon, PE D'Souza, DB Barr, PB Ryan	04/02/2020
Serum concentrations of polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the Michigan PBB Registry 40 years after the PBB contamination incident. Environment international	CJ Chang, ML Terrell, M Marcus, ME Marder, P Panuwet, PB Ryan, M Pearson, H Barton, DB Barr	04/01/2020
Design and Rationale of the Biomarker Center of the Household Air Pollution Intervention Network (HAPIN) Trial. Environmental health perspectives	DB Barr, N Puttaswamy, LM Jaacks, K Steenland, S Rajkumar, S Gupton, PB Ryan, K Balakrishnan, JL Peel, W Checkley, T Clasen, ML Clark	04/01/2020
Perspectives on Heavy Metal Soil Testing Among Community Gardeners in the United States: A Mixed Methods Approach. International journal of environmental research and public health	CM Hunter, DHZ Williamson, MO Gribble, H Bradshaw, M Pearson, E Saikawa, PB Ryan, M Kegler	07/03/2019
Quantification of malondialdehyde in exhaled breath condensate using pseudo two-dimensional ultra-performance liquid chromatography coupled with single quadrupole mass spectrometry. Journal of chromatography. B, Analytical technologies in the biomedical and life sciences	K Kartavenka, P Panuwet, R Greenwald, KM Ehret, PE D'Souza, DB Barr, PB Ryan	01/15/2019
Investigation of associations between exposures to pesticides and testosterone levels in Thai farmers. Archives of environmental & occupational health	P Panuwet, C Ladva, DB Barr, T Prapamontol, JD Meeker, PE D'Souza, H Maldonado, PB Ryan, MG Robson	07/04/2018
Degradation of Organophosphorus and Pyrethroid Insecticides in Beverages: Implications for Risk Assessment. Toxics	SA Radford, P Panuwet, RE Hunter, DB Barr, PB Ryan	02/02/2018
Quantification of Polybrominated and Polychlorinated Biphenyls in Human Matrices by Isotope-Dilution Gas Chromatography-Tandem Mass Spectrometry. Journal of analytical toxicology	ME Marder, P Panuwet, RE Hunter, PB Ryan, M Marcus, DB Barr	09/01/2016
A single method for detecting 11 organophosphate pesticides in human plasma and breastmilk using GC-FPD. Journal of chromatography. B, Analytical technologies in the biomedical and life sciences	W Naksen, T Prapamontol, A Mangklabruks, S Chantara, P Thavornyutikarn, MG Robson, PB Ryan, DB Barr, P Panuwet	07/01/2016
Production of Insecticide Degradates in Juices: Implications for Risk Assessment. Journal of agricultural and food chemistry	SA Radford, P Panuwet, RE Hunter, DB Barr, PB Ryan	06/08/2016
Resolving uncertainty in the spatial relationships between passive benzene exposure and risk of non-Hodgkin lymphoma. Cancer epidemiology	JM Switchenko, C Bulka, K Ward, JL Koff, AR Bayakly, PB Ryan, LA Waller, CR Flowers	04/01/2016
Biological Matrix Effects in Quantitative Tandem Mass Spectrometry-Based Analytical Methods: Advancing Biomonitoring. Critical reviews in analytical chemistry	P Panuwet, RE Hunter, PE D'Souza, X Chen, SA Radford, JR Cohen, ME Marder, K Kartavenka, PB Ryan, DB Barr	01/01/2016
Associations of maternal organophosphate pesticide exposure and PON1 activity with birth outcomes in SAWASDEE birth cohort, Thailand. Environmental research	W Naksen, T Prapamontol, A Mangklabruks, S Chantara, P Thavornyutikarn, N Srinual, P Panuwet, PB Ryan, AM Riederer, DB Barr	10/01/2015
Neurobehavioral effects of exposure to organophosphates and pyrethroid pesticides among Thai children. Neurotoxicology	N Fiedler, J Rohitrattana, W Siriwong, P Suttiwan, P Ohman Strickland, PB Ryan, DS Rohlman, P Panuwet, DB Barr, MG Robson	05/01/2015
Method for the quantification of current use and persistent pesticides in cow milk, human milk and baby formula using gas chromatography tandem mass spectrometry. Journal of chromatography. B, Analytical technologies in the biomedical and life sciences	X Chen, P Panuwet, RE Hunter, AM Riederer, GC Bernoudy, DB Barr, PB Ryan	11/01/2014
HPLC-MS/MS method for the measurement of insecticide degradates in baby food. Journal of agricultural and food chemistry	SA Radford, P Panuwet, RE Hunter, DB Barr, PB Ryan	07/23/2014
Biomarker-based calibration of retrospective exposure predictions of perfluorooctanoic acid. Environmental science & technology	HM Shin, K Steenland, PB Ryan, VM Vieira, SM Bartell	05/20/2014
Cross validation of gas chromatography-flame photometric detection and gas chromatography-mass spectrometry methods for measuring dialkylphosphate metabolites of organophosphate pesticides in human urine. International journal of hygiene and environmental health	T Prapamontol, K Sutan, S Laoyang, S Hongsibsong, G Lee, Y Yano, RE Hunter, PB Ryan, DB Barr, P Panuwet	01/01/2014
Organophosphate pesticide exposure in school-aged children living in rice and aquacultural farming regions of Thailand. Journal of agromedicine	J Rohitrattana, W Siriwong, T Tunsaringkarn, P Panuwet, PB Ryan, DB Barr, MG Robson, N Fiedler	01/01/2014
Human exposures to PAHs: an eastern United States pilot study. Environmental monitoring and assessment	R Williams, C Croghan, PB Ryan	01/01/2013
Have regulatory efforts to reduce organophosphorus insecticide exposures been effective? Environmental health perspectives	AL Clune, PB Ryan, DB Barr	04/01/2012
Cooking fuel type, household ventilation, and the risk of acute lower respiratory illness in urban Bangladeshi children: a longitudinal study. Indoor air	EL Murray, L Brondi, D Kleinbaum, JE McGowan, C Van Mels, WA Brooks, D Goswami, PB Ryan, M Klein, CB Bridges	04/01/2012
Agricultural Pesticide Management in Thailand: Situation and Population Health Risk. Environmental science & policy	P Panuwet, W Siriwong, T Prapamontol, PB Ryan, N Fiedler, MG Robson, DB Barr	03/01/2012
Quantification of melamine in human urine using cation-exchange based high performance liquid chromatography tandem mass spectrometry. Journal of chromatography. B, Analytical technologies in the biomedical and life sciences	P Panuwet, JV Nguyen, EL Wade, PE D'Souza, PB Ryan, DB Barr	03/01/2012
Rainfall, household crowding, and acute respiratory infections in the tropics. Epidemiology and infection	EL Murray, M Klein, L Brondi, JE McGowan, C van Mels, WA Brooks, D Kleinbaum, D Goswami, PB Ryan, CB Bridges	01/01/2012
Retrospective exposure estimation and predicted versus observed serum perfluorooctanoic acid concentrations for participants in the C8 Health Project. Environmental health perspectives	HM Shin, VM Vieira, PB Ryan, K Steenland, SM Bartell	12/01/2011
Environmental fate and transport modeling for perfluorooctanoic acid emitted from the Washington Works Facility in West Virginia. Environmental science & technology	HM Shin, VM Vieira, PB Ryan, R Detwiler, B Sanders, K Steenland, SM Bartell	02/15/2011
Current and historically used pesticides in residential soil from 11 homes in Atlanta, Georgia, USA. Archives of environmental contamination and toxicology	AM Riederer, KD Smith, DB Barr, SW Hayden, RE Hunter, PB Ryan	05/01/2010
Method for the determination of organophosphorus and pyrethroid pesticides in food via gas chromatography with electron-capture detection. Journal of agricultural and food chemistry	RE Hunter, AM Riederer, PB Ryan	02/10/2010
Rate of decline in serum PFOA concentrations after granular activated carbon filtration at two public water systems in Ohio and West Virginia. Environmental health perspectives	SM Bartell, AM Calafat, C Lyu, K Kato, PB Ryan, K Steenland	02/01/2010
Pyrethroid and organophosphorus pesticides in composite diet samples from Atlanta, USA adults. Environmental science & technology	AM Riederer, RE Hunter, SW Hayden, PB Ryan	01/01/2010
Reduced PM2.5 in Trujillo, Peru, on El Dia Sin Autos ("The Day Without Cars"). Journal of environmental health	BE Cassidy, M Aguilar-Villalobos, PB Ryan, LP Naeher	01/01/2010
Association of ambient ozone exposure with airway inflammation and allergy in adults with asthma. The Journal of asthma : official journal of the Association for the Care of Asthma	SB Khatri, FC Holguin, PB Ryan, D Mannino, SC Erzurum, WG Teague	10/01/2009
Predictors of personal air concentrations of chloroform among US adults in NHANES 1999-2000. Journal of exposure science & environmental epidemiology	AM Riederer, SM Bartell, PB Ryan	03/01/2009
Exposure information in environmental health research: current opportunities and future directions for particulate matter, ozone, and toxic air pollutants. Journal of exposure science & environmental epidemiology	TE McKone, PB Ryan, H Ozkaynak	01/01/2009
Diet and nondiet predictors of urinary 3-phenoxybenzoic acid in NHANES 1999-2002. Environmental health perspectives	AM Riederer, SM Bartell, DB Barr, PB Ryan	08/01/2008