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Public Health Aerobiology, Virology and Exhaled Biomarker Laboratory (PHAB Lab)

Studying Airborne Infection Transmission

Dr. Donald Milton testing out his machine with a student

The laboratory supports studies of:

  • airborne infection transmission
  • influenza epidemiology
  • bioaerosol exposure in asthma
  • non-invasive monitoring of exhaled biomarkers

Capabilities of the lab include culturing viruses, RTqPCR, analysis of exhaled breath particles, bioaerosol sampling and immunoassay.

Department: Applied Environmental Health (MIAEH)
Room Number: 0110, 0117, 0120, 2131A
Director: Donald Milton

Office Phone Number: (301) 405-3142

The PHAB Lab is led by Dr. Donald Milton. The lab studies infectious diseases and currently is studying COVID-19 in our StopCOVID study.



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Our sponsors include:


UMD StopCOVID illustration



Recent Publications From the UMD StopCOVID Team

Prather K, Marr L, Schooley R, McDiarmid M, Wilson M, Milton DK. Airborne Transmission of SARS-CoV-2, Science 05 Oct 2020

Milton DK. A Rosetta Stone for Understanding Infectious Drops and Aerosols. J Pediatric Infect Dis Soc 2020
(accepted manuscript here if you cannot access journal webpage)

Morawska L, Milton DK. It is Time to Address Airborne Transmission of COVID-19. Clin Infect Dis 2020

Bueno de Mesquita PJ, Noakes CJ, Milton DK. Quantitative aerobiologic analysis of an influenza human challenge-transmission trial. Indoor Air 2020

Bueno de Mesquita PJ, Nguyen-Van-Tam J, Killingley B, et al. Influenza A (H3) illness and viral aerosol shedding from symptomatic naturally infected and experimentally infected cases. Influenza Other Respir Viruses 2020; irv.12790.

Chia PY, Coleman KK, Tan YK, et al. Detection of air and surface contamination by SARS-CoV-2 in hospital rooms of infected patients. Nature Communications 2020;11(1):2800.

Morawska L, Tang JW, Bahnfleth W, et al. How can airborne transmission of COVID-19 indoors be minimised? Environ Int 2020;142:105832.

Nguyen-Van-Tam JS, Killingley B, Enstone J, et al. Minimal transmission in an influenza A (H3N2) human challenge-transmission model within a controlled exposure environment. PLoS Pathog 2020;16(7):e1008704.

Leung NHL, Chu DKW, Shiu EYC, et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nature Medicine 2020;1–5.

Zhu S, Jenkins S, Addo K, et al. Ventilation and laboratory confirmed acute respiratory infection (ARI) rates in college residence halls in College Park, Maryland. Environment International 2020;137:105537.

Fennelly KP, Acuna-Villaorduna C, Jones-Lopez E, Lindsley WG, Milton D. Microbial Aerosols: New Diagnostic Specimens for Pulmonary Infections. CHEST [Internet] 2019 [cited 2019 Nov 20];0(0).

Yan J, Grantham M, Pantelic J, et al. Infectious virus in exhaled breath of symptomatic seasonal influenza cases from a college community. Proc Natl Acad Sci USA 2018;115(5):1081–6.

Principal Investigator: Dr. Donald Milton

Research and Clinical Faculty: Dr. Barbara Albert, Dr. Jennifer German, Dr. Sheldon Tai, Dr. Somayeh Youssefi

Faculty Specialists: Dr. Filbert Hong, Isabel Sierra Maldonado

Staff: Yi Esparza, Aaron Kassman, Michael Lutchenkov, Maria Schanz, Delwin Suraj, Faith Touré, Rhonda Washington-Lewis

Postdoctoral Associates: Dr. P. Jacob Bueno de Mesquita, Dr. Sanmi Adenaiye

Graduate Research Associates: Jianyu Lai

See the website of our current project: UMD StopCOVID

StopCOVID study



Inquire at


Find out how people transmit COVID-19 and how to prevent transmission:

  1. How much airborne virus does an infected person exhale?
  2. How much virus is released into the air when an infected person breathes, talks, or sings?
  3. How well do surgical and homemade masks block release of airborne virus?

Another goal is to gather samples that can be used to better understand how the body fights the infection.

UMD StopCOVID illustration
Illustration of how viruses spread via air from an infected person, both with and without a mask.
  • Kingfisher Duo nucleic acid preparation workstation
  • QuantStudio7 with TaqMan Array Card qPCR system
  • Two Qiagen QiaCube robotic nucleic acid preparation workstations
  • Agilent Mx3005P qPCR system
  • Biotek ELX808IU and FLX800TBIE visible and fluorescence temperature controlled kinetic microplate readers,
  • three CO2 incubators,
  • a biosafety cabinet,
  • two Gesundheit-II human exhaled aerosol collectors (an additional device at National University of Singapore)
  • a human exhaled aerosol droplet sampler with cryogenic impactor ("IcePac")
  • four Pulmatrix Exhalair exhaled particle analyzer and collectors
  • assorted aerosol generators for liquid droplet and dry aerosols
  • HEPA filtered glove box and large chamber for aerosol containment
  • Vaisala CO2 monitors
  • air sampling pumps
  • and upper-room UVC fixtures.




Prometheus@UMD diagram







Website (historical):

  1. Identify and characterize contagious phenotype of acute respiratory infection (ARI)
  2. Identify biomarkers of infection and contagiousness
  3. Test wearable sensors for early detection of ARI & outbreaks
  4. Collect PBMCs for identification of epigenetic markers of infection
  5. Characterize the role of aerosols and built environment in ARI transmission
Description of Effort:
  • Enroll a longitudinal cohort and obtain baseline serology
  • Identify index cases of ARI using 45plex TAC assay & enroll contacts
  • Follow contacts with daily respiratory swabs and blood samples
  • Characterize viral shedding in resp. & fomite swabs, and exhaled breath
  • Confirm transmission events through phylogenetics sequencing
  • Monitor indoor environment CO2, temperature, rel. humidity, and estimate re-breathed air exposures
  • Analyze peripheral blood via RNA sequencing from days before onset of infection for biomarkers of infection and contagiousness
  • Cohort in the Wild
  • Fully computerized consent, questionnaire, & lab data collection
  • Daily surveys for respiratory symptoms (via text SMS)
  • Built Environment – natural experiment – high/low ventilation dorms
  • Virology and Infectious Disease (PHAB Lab & Frieman Lab at UMSOM)
  • Bioinformatics, Biostatistics (phylogenetics, machine learning)
  • Antigen arrays/Immunome (Felgner Lab at UC-Irvine)
  • Aerobiology and exhaled biomarkers (aerosol shedding)
  • Mechanical Engineering (indoor air, ventilation)
  • Computer Science (location tracking)
  • Student research assistants – lab and clinical experience


Year 1 (spring 2017): $1.6M
  • Longitudinal cohort: 74 students
  • 72 ARI cases; 60 contacts followed; PAXgene: 123 total, 7 Day 0/-1
  • 9 Flu A, 1 FluB, 15 AdV, 3 RSVA, 9 RSVB, 25 hCoV, 4 hPIV
Year 2 (2017-2018): $2.5M
  • Longitudinal cohort: 284 students
  • 76 ARI cases; 70 contacts followed; PAXgene 193 total, 8 Day 0/-1
  • 6 Flu A, 9 Flu B, 5 AdV, 4 RSVB, 24 hCoV, 13 hPIV, 1 hMPV
Year 3 (2018-2019): $2.9M
  • Longitudinal cohort: 575 participants
  • 211 ARI cases screened; 137 contacts followed
  • PAXgene: 927 total, 44 Day 0/-1; PBMC 339 total, 43 acute ARI
  • Daily text message, average response rate: 248
  • Wearable devices deployed: 150; 29 validated ARI among users
  • 27 Flu A, 4 AdV, 3 RSVA, 6 RSVB, 56 hCoV, 11 hPIV, 11 hMPV
Year 4 (2019-20): $2.1M
  • Wearable devices cohort: 250
  • 78 ARI cases screened; 46 contacts followed
  • PAXgene: 384 sample-days, 32 Day 0/-1
  • 3 Flu A, 6 Flu B, 1 RSVA, 1 RSVB, 18 hCoV, 2 hPIV, 7 hMPV