Professor of Environmental Health, Applied Environmental Health (MIAEH)
Affiliate in Cell Biology and Molecular Genetics; Professor, Internal Medicine, University of Maryland School of Medicine
Other Affiliations: Epidemiology and Biostatistics, UMD Prevention Research Center
Campus: UMD | Building: School of Public Health | Room: 2234V
Phone: 301-405-0389 |
Laboratory Website: 
Bioaerosol, Virology, and Exhaled Biomarker Laboratory
Bioaerosol, Virology, and Exhaled Biomarker Laboratory

I am actively pursuing multidisciplinary investigations of the health effects of bioaerosols with three major themes: 1) investigation and prevention of airborne infection transmission and applications to biodefense, 2) exhaled breath analysis, and 3) the relationship of asthma onset and exacerbation to exposure to allergens and microbial products. Currently, my research on mechanisms and prevention of airborne infection transmission is focused on influenza. Our recent publication in PLoS Pathogens demonstrated for the first time that 8.8 fold greater numbers of influenza virus particles are present in fine exhaled droplets than in large respiratory droplets and that the fine aerosol droplets are infectious. I am currently co-PI of the EMIT project (Evaluating modes of influenza transmission in a human challenge model), a $10.8M study to define the role of aerosols in human-to-human transmission of influenza virus. A recent review examines the likely role aerosols played in transmission of smallpox. A mathematical model we developed to describe the relationship between indoor air quality and airborne infection is being used to understand and control risks of drug resistant TB transmission. Other work in my lab includes productivity effects of rhinovirus colds in office workers and asthmatic children, occupational asthma, outdoor allergens and asthma, and laboratory and epidemiological studies of control methods for influenza and agents of biological warfare and terrorism. Exhaled breath analysis is a unifying theme of our work with ongoing studies of on exhaled gas and particle phase biomarkers for lung inflammation in asthma and characterization of the personal exposome, and studies of exhaled particles as the vehicle of airborne communicable disease transmission.

I earned a BS in Chemistry from the University of Maryland Baltimore County (Cum Laude), an MD from Johns Hopkins University and a DrPH (Environmental Health) from Harvard University. I trained clinically in medicine at Emory and Boston Universities and Occupational and Environmental Medicine at Harvard. I previously served on the faculties of the Department of Environmental Health, Harvard School of Public Health and the Department of Work Environment, University of Massachusetts Lowell School of Health and Environment. Currently, I am Professor and Director of the Maryland Institute for Applied Environmental Health, University of Maryland School of Public Health and Professor of Medicine, University of Maryland School of Medicine, Adjunct Senior Lecturer on Occupational and Environmental Health at Harvard School of Public Health, and Honorary Professor, Department of Community Medicine, University of Hong Kong. I am board certified in internal and occupational medicine and have 20 years of experience in occupational medicine referral practice. I teach courses on environmental and occupational hygiene, aerobiology, toxicology, indoor air quality, respiratory epidemiology, physiology, pathology, pathophysiology. I am a past chair of the ACGIH Bioaerosols committee and a member of the editorial boards of Indoor Air and BMC Public Health, and for 10 years of Applied Environmental Microbiology. I am a recipient of the Lloyd Hyde Research Award of Emory University, the Harriet Hardy Award for Lifetime Achievement from the New England College of Occupational and Environmental Medicine, and was elected a Fellow of the International Society for Indoor Air Quality and Climate in 2008.


Education and Training
  • Dr.P.H., Environmental Health, Harvard University; M.D., Johns Hopkins University; B.S., Chemistry (Cum Laude), University of Maryland Baltimore County
  • Residency in Internal Medicine: Emory University - Grady Hospital, Atlanta, GA and Boston University Hosptal
  • Residency in Occuapational and Environmental Medicine, Harvard School of Public Health
  • Board Certified in Internal Medicine and Occupational and Environmental Medicine