News & Publications

Markham interviewed Dr. Kristen Coleman of the University of Maryland about her co-authored study, "Viral Load of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Respiratory Aerosols Emitted by Patients With Coronavirus Disease 2019 (COVID-19) While Breathing, Talking, and Singing."

Link: New study shows "fine aerosols" play big role in transmitting COVID-19

GUV & Indoor Air Articles

The New York Times (November 20, 2023)

Quoted and pictured Dr. Milton

Link: Why We're Still Breathing Dirty Indoor Air

MarylandToday (November 1, 2022)

Mentioned a record-breaking Balvi gift of $9.4 million to the PHAB Lab to study GUV

Link: Record-breaking $9.4M Crypto Gift to Fund Study of Air Disinfection to Prevent Future Pandemics

The Diamondback (February 22, 2022)

Quoted Dr. Kate McPhaul on DR-boxes

Link: UMD students, faculty build low-cost air filtration devices

CBS News (May 10, 2022)

Interview of Dr. Milton on GUV Technology

Link: Researchers testing light technology that could protect against the next pandemic

The New York Times (April 22, 2022)

Opinion Piece by Dr. Milton, Edward A. Nardell, and David Michaels

Link: We Have the Technology to Stop Superspreading Without Masks

Statements

Statement of Scientists in Response to CDC’s May 7th Announcement Recognizing Inhalation Exposure

We are pleased that in its updated Scientific Brief: SARS-CoV-2 Transmission CDC acknowledged today that transmission of the SARS-CoV-2 virus through inhalation of tiny aerosol particles is a primary route of exposure and that risk of inhaling the virus is greatest close to an infected person. This is an important and major step forward.

[Note (May 11): the CDC has recently made improvements to the How COVID-19 Spreads website.]

However, we are concerned that CDC’s accompanying document How COVID-19 Spreads is misleading, and potentially harmful. ... [expand to read more]

In that document CDC says that breathing in small droplets and particles (i.e., aerosols) that contain the virus when people are far apart or have been in the same enclosed space for more than a few minutes is UNCOMMON (our emphasis). This will lead people to continue to think that maintaining distance is sufficient to prevent transmission.

We know that transmission at distances beyond 6 feet occurs because of superspreader events, careful studies of smaller outbreaks, and the physics of aerosols. It can easily happen indoors in a poorly ventilated environment, when people are not wearing masks.

There is clear consensus among aerosol scientists and epidemiologists that inhalation of small aerosol particles, including at distances of greater than six feet, is a major driver of the COVID-19 pandemic. To slow transmission and save lives, it is crucial that CDC update its guidance and recommendations to address and highlight the importance of improved ventilation and using NIOSH approved respirators, especially in indoor locations where the virus may accumulate in the air.

Moreover, OSHA must issue an Emergency Temporary Standard to control workplace exposures, including inhalation exposure, as soon as possible in order to protect workers and reopen the economy safely.

As CDC has made clear, vaccination alone will not stop this pandemic. Mitigation measures are also needed to limit exposures. We must control inhalation exposure of small aerosol particles to end this pandemic.

CDC must immediately update and strengthen its guidelines and recommendations to protect the public and workers for inhalation exposures to SARS-CoV-2.

More on the importance of addressing aerosol transmission and the steps needed to control exposures can be found in the letter several of us sent to federal COVID-19 leaders in February 2021.

David Michaels, PhD, MPH

Professor, Department of Environmental and Occupational Health

Milken Institute School of Public Health

The George Washington University

Former Assistant Secretary if Labor for OSHA (2009-2017)

drdavidmchaels@gmail.com

Donald K. Milton, MD, DrPH

Professor, Institute for Applied Environmental Health

Department of Epidemiology and Biostatistics

University of Maryland School of Public Health

dmilton@umd.edu

301-405-0389

Linsey C. Marr, PhD

Professor, Civil and Environmental Engineering

Center for Emerging, Zoonotic, and Arthropod-Borne Pathogens

Virginia Tech

lmarr@vt.edu and mediarelations-g@vt.edu

Lisa M Brosseau, ScD, CIH

Professor (retired)

Research Consultant, University of Minnesota, Center for Infectious Disease Research and Policy

brosseau@umn.edu

Peg Seminario

Safety and Health Director, AFL-CIO (retired)

pseminario228@gmail.com

Kimberly A. Prather, Ph.D.

Director, NSF Center for Aerosol Impacts on Chemistry of the

Environment

Distinguished Professor

Distinguished Chair in Atmospheric Chemistry

Scripps Institution of Oceanography

University of California, San Diego

kprather@ucsd.edu

Michael T. Osterholm, PhD, MPH

Regents Professor, McKnight Presidential Endowed Chair in Public Health

Director, Center for Infectious Disease Research and Policy

University of Minnesota

mto@umn.edu

What to do about K-12 Schools?

Background: The CDC was slow to accept that inhalation of viral aerosols is how many people get infected... [expand to read more]

for both reasons of backwardness of the medical-hospital infection control profession and political influences of the AHA and corporate medicine. Their guidance’s list of the five key prevention strategies for K-12 schools, even with the 19 March 2021 update is still not consistent with the scientific evidence. It does not list ventilation, an effective engineering control, as the first key strategy. The general public knows airborne transmission is a reality and the importance of inhalation exposure to infectious aerosols has been extensively covered by CBS, MSNBC, NPR, the Washington Post, the New York Times, the Atlantic and many other mainstream media to the point that a Post journalist told me on March 19th that the topic wasn’t even considered newsworthy anymore. This lack of science-based guidance from CDC, focusing on surface cleaning and not air cleaning, severely complicates the situation for decision makers.

As of March 20, 2021, we are still at high, and most recently, increasing levels of transmission in Maryland and the US generally, even though we are down from the tragic peak levels of early January. This is not a time to relax our vigilance. But we do know enough today, that if we employ the science, we can make schools and workplaces safer and mitigate the serious impacts of school and workplace closures by opening up with stringent controls – and by that I mean not just mask mandates.

The science of worker and building occupant protection from hazardous aerosols and the hierarchy of effective controls is well established. Following the hierarchy of control, it is key to put engineering strategies in place before much less-effective controls that rely on human behavior. The CDC’s recommendations, viewed in light of this hierarch is completely upside down, putting individual behaviors first (masks, distancing, and handwashing) and cleaning and administrative controls (contract tracing) last. Furthermore, the CDC completely fails to specifically recommend the single most effective intervention, ventilation. Instead, they bury mention of ventilation behind sanitizing doorknobs, even though their own scientific briefs acknowledge that touching contaminated objects doesn’t seem to be an important mode of transmission.

Here are Dr. Milton's recommendation for five key prevention strategies for K-12 schools:

Ventilation – keep CO2 concentrations as low as possible consistent with occupant comfort and implement multiple room filtration units (≥80% efficiency for smoke or HEPA filters) with vertically oriented exhaust to achieve a total clean air delivery of ≥ 4 air changes per hour and 10 liters/sec/person. [Engineering Control]
Contact tracing in combination with isolation and quarantine [Administrative Control]
Move meals outdoors [Administrative Control] or install upper-room germicidal ultraviolet air sanitation for lunchrooms (see lectures and guides) [Engineering Control]
Masks and respirators – provide all occupants with masks with >80% filtration efficiency for 0.3 µm particles with leakage ratios ≥10 and N95 respirators for staff. [Human Behavior]
Handwashing and respiratory etiquette [Human Behavior]

Extensive surface decontamination is not a key control. Upgrading normal cleaning practices and use of EPA listed cleaning agents effective against coronaviruses should be encouraged especially where this has been reduced by fiscal constraints on school budgets. These recommendations are in line with the well-established hierarchy of controls and the scientific evidence about how COVID-19 spreads. Ionization technologies are not proven solutions -- ventilation, filtration, and ultraviolet air sanitation are.

What to do about musical performance

See the results of the U Colorado - UMD study funded by a coalition of performing arts organizations.

Better fitting masks

To be better protected against inhaling virus floating in the air ... [expand to read more about how and why]

To be better protected against inhaling virus floating in the air (and to release less too if you are infected), better fitting masks are important. William Lindsley, a research bioengineer at NIOSH, presented his research at a UMD SPH MIAEH seminar on March 23 showing that there are several ways to make a mask better. Many surgical / medical procedure masks have good filters (not all unfortunately, some good brands are Ambrust and Zubrex, there are others), but they leak a lot around the edges (foggy glasses anyone?). So, get them to fit tighter and leak less you can use a mask brace, a tight fitting cloth mask over the medical mask, or tuck the mask. The brace is best, a cloth mask is good (depends on the mask), and tucking works pretty well too. Tucking seems tricky, but if you watch this video from UNC, it helps get the hang of it.

Previous News & Publications

Click the dropdown arrow to discover more of our previous work in the news and publications

News Articles

D.C.-area health officials urge precautions as coronavirus cases rise The Washington Post, July 30, 2022
2 COVID experts say they are wearing masks outside when it's crowded as the highly infectious Omicron BA.5 variant spreads Insider, July 13, 2022
Monkeypox Can Be Airborne, Too The New York Times, June 7, 2022
The Covid Roulette: The Hard Truth About The WHCA Dinner The Pavlovic Today, May 11, 2022
We Have the Technology to Stop Superspreading Without Masks The New York Times, April 21, 2022
Coronavirus FAQ: I'm a one-way masker. With mask mandates going away, is that helpful? NPR. April 19, 2022.
What do we know about “stealth omicron” so far? Associated Press. ABC News. PBS. April 12, 2022.
Saliva Testing for COVID-19 Quicker, Safer Than Nasal Swabs ASM, March 21, 2022
Saliva testing for COVID-19 accurate, provides earlier diagnosis, study finds UPI, March 21, 2022
Is omicron leading us closer to herd immunity against COVID-19? Associated Press, February 23, 2022
Which masks are safest? Schools around the country struggle to answer. The Washington Post. Jan 28, 2022.
Want to keep omicron away? Wear a better mask, like the N95. Tampa Bay Times, January 25, 2022
How do I know if I have a cold, the flu or COVID-19? Associated Press, ABC News, The Seattle Times January 7, 2022
Omicron is spreading at lightning speed. Scientists are trying to figure out why, December 31, 2021
Is the Coronavirus Getting Better at Airborne Transmission? The New York Times, October 1, 2021
New studies hint that the coronavirus may be evolving to become more airborne, ScienceNews, August 17, 2021
The virus is an airborne threat, the C.D.C. acknowledges. New York Times, May 7, 2021.
Ask KHN-PolitiFact: I’ve Recovered From Covid. Why Do I Still Have to Mask Up? Kaiser Health News, April 16, 2021
How one restaurant’s experiment may help diners breathe safely, Washington Post, April 14, 2021
Has the Era of Overzealous Cleaning Finally Come to an End? New York Times, April 8, 2021
As vaccinations increase, you may want to dine indoors again. Here’s what to consider. Washington Post, March 19, 2021
Three Feet or Six? Distancing Guideline for Schools Stirs Debate, New York Times, March 16, 2021
Will schools fully reopen? It may depend on whether students have to sit six feet apart. Washington Post, March 11, 2021
Answering COVID's Big Questions on Campus. Maryland Today, October 6, 2020.
Pandemic Advances Scientific Understanding Of Viruses' Air Transmission, All Things Considered, NPR, December 28, 2020
For Scientists Who Study Virus Transmission, 2020 Was A Watershed Year. NPR article by Nel Greenfieldboyce, December 26, 2020
Indoor Dining and the Spread of Coronavirus. Dr. Milton was on the Brian Lehrer Show WNYC, December 15, 2020
CNN.com: Here's why mouthwash is not going to save you from coronavirus (November 17, 2020)
UMD Scientists Say Vice Presidential Debate Needs Air Filtration System Due To Coronavirus. CBS Baltimore, October 7, 2020.
The plexiglass barriers at tonight’s debate will be pretty useless, virus experts say. New York Times, October 7, 2020.
Beyond Plexiglass: Scientists Say This Simple Solution Could Keep VP Debate Safer. NPR, October 7, 2020.
Answering COVID's Big Questions on Campus. Maryland Today, October 6, 2020.
A Letter to the Commission on Presidential Debates regarding debate safety (October 6, 2020)
Maryland Public Health Association Panel: (Re)Opening Safely: An Occupational Health and Safety Perspective, Dr. Milton and Dean Lushniak joined Union Leaders and former OSHA Director Dr. David Michaels (November 5, 2020)
We Need to Talk About Ventilation. Tufekci Z. The Atlantic. July 30, 2020.
The Flu May Linger in the Air, Just Like the Coronavirus, The New York Times, July 14, 2020.
Dr. Milton's lecture for MIEH 688: Infectious Drops and Aerosols (September 22, 2020)
NPR.org: Dr. Milton on All Things Considered: "Pandemic Advances Scientific Understanding Of Viruses' Air Transmission" (Dec 28, 2020)
Virtual Press Conference on COVID-19 Science Letter (October 5, 2020)

Lectures by Members of the StopCOVID@UMD Team

Keeping Public Spaces Safe: Germicidal Ultraviolet Light for Air Sanitation During COVID-19
Dr. Milton joined the Harvard Kennedy School, and Harvard Global Health Institute, to talk about the safety and evidence base supporting the use of upper room germicidal ultraviolet light (UR-GUV) on February 25, 2021.
Maryland Public Health Association Panel: (Re)Opening Safely: An Occupational Health and Safety Perspective Dr. Milton and Dean Lushniak joined Union Leaders and former OSHA Director Dr. David Michaels (November 5, 2020)
Keynote Address for The Aerosol Society (UK): Building bridges from aerosol science to clinical infectious disease practice , Dr. Milton (October 7, 2020)
Virtual Press Conference on COVID-19 Science Letter (October 5, 2020)
Dr. Milton's lecture for MIEH 688: Infectious Drops and Aerosols (September 22, 2020)
National Academies Workshop on Airborne Transmission of SARS-CoV-2 (August 26-27, 2020, Talk #9, Dr. Milton: Viruses in Respiratory Droplets)
University of California San Francisco Medical Grand Rounds, Dr. Milton (July 16, 2020)
A Conversation: What Do Science and Data Say About the Near Term Future of Singing, Dr. Milton (May 12, 2020)
Transmission Perspective on COVID-19 and the Future of Singing, Dr. Milton (May 5, 2020)

Publications from StopCOVID@UMD Team

Lai, J., German, J., Hong, F., Tai, S.-H. S., McPhaul, K. M., & Milton, D. K. (2022). Comparison of saliva and midturbinate swabs for detection of SARS-COV-2. Microbiology Spectrum, 10(2). https://doi.org/10.1128/spectrum.00128-22
Oluwasanmi O Adenaiye, Jianyu Lai, P Jacob Bueno de Mesquita, Filbert Hong, Somayeh Youssefi, Jennifer German, S-H Sheldon Tai, Barbara Albert, Maria Schanz, Stuart Weston, Jun Hang, Christian Fung, Hye Kyung Chung, Kristen K Coleman, Nicolae Sapoval, Todd Treangen, Irina Maljkovic Berry, Kristin Mullins, Matthew Frieman, Tianzhou Ma, Donald K Milton, University of Maryland StopCOVID Research Group, Infectious Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Exhaled Aerosols and Efficacy of Masks During Early Mild Infection, Clinical Infectious Diseases, 2021;, ciab797, DOI: 10.1093/cid/ciab797
Morawska, L., Allen, J., Bahnfleth, W., Bluyssen, P.M., Boerstra, A., Buonanno, G., ... Yao, M. (2021, May 14). A paradigm shift to combat indoor respiratory infection. Science. 10.1126/science.abg2025
Adenaiye, O., Bueno de Mesquita, P. J., Wu, Q., Hong, F., Lai, J., Chen, S., & Milton, D. K. (2021). The effect of Covid‐19 Stay‐at‐home order and campus closure on the prevalence of acute respiratory infection symptoms in college campus cohorts. Influenza and Other Respiratory Viruses, 15(3), 331–335. https://doi.org/10.1111/irv.12837
Prather K, Marr L, Schooley R, McDiarmid M, Wilson M, Milton DK. Airborne Transmission of SARS-CoV-2, Science 05 Oct 2020. DOI: 10.1126/science.abf0521
Milton DK. A Rosetta Stone for Understanding Infectious Drops and Aerosols. J Pediatric Infect Dis Soc 2020;Available from: https://academic.oup.com/jpids/article/doi/10.1093/jpids/piaa079/5875939 (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;Available from: https://academic.oup.com/cid/article/doi/10.1093/cid/ciaa939/5867798
Bueno de Mesquita PJ, Noakes CJ, Milton DK. Quantitative aerobiologic analysis of an influenza human challenge-transmission trial. Indoor Air 2020;Available from: https://onlinelibrary.wiley.com/doi/abs/10.1111/ina.12701
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. https://onlinelibrary.wiley.com/doi/abs/10.1111/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. https://www.nature.com/articles/s41467-020-16670-2
Morawska L, Tang JW, Bahnfleth W, et al. How can airborne transmission of COVID-19 indoors be minimised? Environ Int 2020;142:105832. https://www.sciencedirect.com/science/article/pii/S0160412020317876?via%3Dihub
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. https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1008704
Leung NHL, Chu DKW, Shiu EYC, et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nature Medicine 2020;1–5. https://www.nature.com/articles/s41591-020-0843-2
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. http://www.sciencedirect.com/science/article/pii/S0160412019341108
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). Available from: https://journal.chestnet.org/article/S0012-3692(19)34113-3/abstract
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. https://www.pnas.org/content/115/5/1081

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