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An annotated list of the research and news I've been reading

There's nothing fancy here. Pretty much just a list of info that I will update regularly.

Links will be loosely organized into topics, and will be listed in reverse chronological order, with the most-recently published articles at the top of the section.

Speech and Singing Research

The latest installment of the aerosol and singing study from the University of Colorado in Boulder was released on April 13, 2021. In this study, they examined multiple instruments, a singer, and a theater performer, but concentrated their findings on the singer and the clarinetist. They studied indoor conditions in a small, controlled room, and modeled outdoor conditions, which would include ambient wind. In general, using masks greatly reduced the aerosol plume in front the the singer and the player, but did not eliminate it entirely. Some leakage was found going behind the singer, near the ears, emphasizing the need for a good mask fit by the singer. (This would include the congregation, if there is to be congregational singing.) The researchers recommended any indoor rehearsals to be less than thirty minutes before vacating the room for an air change, and less than 60 minutes outdoors. Risk increased after these durations.


Published March 29, 2021, this article from the BBC relying on the guidance of Professor Cathy Noakes, aerosol scientist in the UK, explains that outdoor transmission is very unlikely.


This study essentially states what we've known for awhile, that people can produce varying amounts of aerosol when they speak, smaller particles containing virus can remain airborne for quite some time, and that mask-wearing greatly reduces the aerosol plume released into the air. Published January 21, 2021.


Peer-reviewed and accepted for publication on September 26, 2020, this case study of the Skagit Valley choir case by aerosol and disease transmission experts posits that aerosol transmission is the most likely cause for the large outbreak of COVID-19 following the rehearsal. Several suggestions are made for making similar situations less risky. Members of the choir and the Skagit Valley Health Department provided detailed information on the rehearsal, which increased the accuracy of the modeling. OF NOTE: The authors mention that while the ballistic/large droplet transmission route is thought to be the most likely mode of transmission by many researchers, there is actually no direct evidence in any of the literature to support this. In other words, there's no reason to discount aerosol transmission when large droplet transmission doesn't have any more evidence.


Twelve singers in an airtight chamber were observed speaking and singing at various pitch and loudness levels. Singing was found to produce more particles, and loud singing produced even more. The procedures were repeated with the participants wearing surgical masks, which reduced visible particles by a great amount. Interestingly, some of the participants were COVID-19 positive at the time of the experiment and no virus particles were found in the air during the experimental phase. There are numerous variables in this experiment that make it a little hard to build policy from, but it is interesting nonetheless.


Harvard/Mass General Grand Rounds hosted Dr. Anthony Fauci on September 10, 2020. In the segment beginning at 15:40 Dr. Fauci specifically states that singing is a risk for transmission. Note too how he mentions at the segment beginning at 16:40 how the type of gathering, rather than a single person who may be a superspreader, is more likely to cause super spreading events.


The National Academies of Science hosted a webinar conference on August 26-27, 2020 that discussed what was known about the transmission of SARS-CoV-2. The proceedings of that meeting were recently released online. The video presentations are also still available at this link. This is a dense document, but has a great deal of information that can be useful in risk mitigation and understanding how the disease transmits. I would urge you to watch the excellent lecture by Dr. Linsey Marr, which is video #6 in the queue. Lecture #8 was also incredibly interesting, giving the origins of the droplets and aerosols from the respiratory tract. Basically, the smaller the particle, the lower in the respiratory tract it likely originated. This has implications for viral load, because the virus likely will be lower in the lungs rather than in the mouth, so smaller particles have the possibility to carry more viral load.


UPDATE: The preprint referenced below was peer-reviewed and accepted for publication on February 5, 2021. The final article version is here.

Non-peer-reviewed preprint posted August 20, 2020 from the PERFORM study, partially funded by the National Public Health of Great Britain. The authors tested singers performing multiple tasks at different volume levels and concluded that the volume at which a singer speaks or sings has a great impact on the amount of aerosols produced. At conversational levels (50-60 dB) the aerosols were similar to breathing, but grew in order of magnitude as the dynamic increased. Recommendations  that guidelines for public singing should be based on the dynamic level of the activity , rather than on the activity type.

Summary of results from the PERFORM study and SOBADRA study. This is not a journal article, but rather a "consensus statement" by the researchers. I particularly find their degrees of confidence on certain conclusions helpful.

The second round of preliminary data from the University of Colorado in Boulder was released in a presentation on August 5, 2020.

0:00-7:52--study and personnel intro

7:52-11:00--video message from Dr. Shelly Miller about aerosols (corrected audio as the initial presentation was garbled)

11:00-18:24--Airborne Particle Spectrometer (APS) of oboe, trombone, low brass, theater performer, and singer

18:2430:08---Flow Visualization Explanation (note especially the videos of the trumpet and oboe toward the end of this section

30:08-37:33--Computational Fluid Dynamics modeling

37:33-39:10--Mask fitting data and recommendations

39:10---1:13:32--Considerations and recommendations

1:13:32-end--closing remarks

NFHS webpage with links to the preliminary research releases from the UC Boulder/UMaryland study. This page is updated regularly with the release of new results.

Safer singing practices, published in Journal of Voice July 2, 2020. The charts in the middle of the paper are particularly helpful for gauging how to move toward the safer end of the continuum.


The CDC released a review of the Skagit Valley Chorale outbreak, which posited that the social aspects of the rehearsal, such as stacking chairs together and sharing snacks may have been probably modes of transmission, while singing may have augmented the transmission. Published online May 15, 2020

Airborne particles in a stagnant air environment can be detected 8-14 minutes after speaking, making airborne transmission of virus particles from speech a "substantial" probability. I mentioned this study in Update #1, and highlighted the findings because this is very concerning. One thing I think we need to remember, however, is that most places, including church sanctuaries, are not completely air stagnant environments. However, knowing this it is important to be aware of the potential for infection from speaking, according to these researchers.

Non-peer reviewed preprint from the University of Nebraska that observes possible airborne transmission of SARS-CoV-2 from infected patients at their medication center. Available online March 26, 2020.

Aerosol emission and superemission during human speech increase with loudness.

This study in Nature from February 2019 is one of the most fundamental to helping us understand the potential dangers of our current situation.

An older article, vital lung capacity, likely from the expiratory phase of singing, is found to be significantly greater in choral singers than in non-singers. Published November 2016. (Vital capacity is the amount of air that can be exhaled after a person inhales their maximum amount. It can be measured in multiple ways. For an explanation of the different types of lung capacity, click here.)


Recommendations for schools from the Johns Hopkins Bloomberg School of Public Health. Many of the recommendations could be helpful for churches, as well. Published May 2021.


Not exactly ventilation related, but good and thorough information on using UV radiation for disinfection from the FDA. Links in the article to the EPA's information are also very helpful.,often%20called%20%22germicidal%22%20lamps.


From the International Society of Indoor Air Quality webinars on December 2, 2020, a series of robust though somewhat technical risk estimators has been provided for general use. Each risk estimator tool has a link to the tool as well as a detailed explanation of what it is intended to be used for and some guidance with how to use it. Lectures are recorded and YouTube links are provided in the linked PDF.


Updated on October 5, 2020, the CDC included aerosol transmission as a possible mode of disease spread. This was a big change, and one that scientists had been calling for for awhile. The change can highlight the need for appropriate ventilation in indoor spaces.


An informative article from the New York Times with several mitigation strategies for indoor environments. Opening windows, filters, and UV sanitation devices are discussed. Published September 27, 2020.


"We Need to Talk About Ventilation" article from The Atlantic, quoting numerous researchers and scientists. Published July 30, 2020.

Published July 15, 2020, the authors of this article recommend limiting occupancy in any space by both the number of people present and the amount of time spent in a space, leaving the room completely every hour to allow for a complete air change, and reducing aerosol-producing activities like singing, loud speaking, and debate.

A blog by Dr. Shelly Miller on what you should consider when looking for ventilation in your indoor spaces.

A 45-minute presentation from Dr. Shelly Miller about ventilation and HVAC. The whole thing has a lot of really good information, but this one had a lot of focus on UV light for elimination of viruses indoors. I highly recommend watching this one. Presented May 1, 2020. 


NIOSH document on germicidal irradiation, specifically aimed toward tuberculosis, but lots of good information for how UV should and should not be used for infection control.


A new mask design unveiled in these articles published March 10 and March 17, 2021, respectively, and possibly available later this year for other singing groups. Details on how to get the masks are not yet available, as far as I can find.


A really interesting release from the NIH on February 23, 2021 suggests that the higher humidity levels created by wearing a mask may help to reduce the severity of COVID-19 infection. Read the press release here and the full journal article available online at the link below. The article was previously online as a preprint, but has since been updated and released ahead of its official publication in the Biophysical Journal.

From November 2020, the Delft University Senselab in the Netherlands tested facemask leakage. Long story short, facemasks range in quality and protection, and they are definitely not fool proof. I recommend using Chrome to look at this webpage, as it's in Dutch and Chrome can do a rough translation.


Published October 30, 2020, this wonderful graphic illustration of how masks work show how particles of different sizes can be trapped by mask particles.

Really helpful podcast from VocalFri, interviewing Dr. John Volckens from Colorado State University. In general, he says that masks work, but there is still some gaps in our knowledge about how well they work. Released online October 21, 2020.


Designing your own masks? This webinar from the Colorado State University researchers Dr. John Volckens and his lab, sponsored by NATS, gives detailed information for what makes a mask effective. What I found the most interesting is that filters in masks likely make them less effective. It's long, at about 90 minutes, but absolutely chock full of good info, especially if you've got folks in your church making masks as a ministry. This is a must-watch for that. Webinar presented September 18, 2020.

Released on July 7, 2020, this video shows the importance of mask fit in reducing aerosol plumes from individuals. Note especially how the plumes produced are greatest behind the dummy's head!


The most powerful argument for the use of masks in preventing the spread of COVID-19 happened right here in my hometown. Two hairstylists who were positive treated nearly 140 clients while wearing masks, and no clients became ill. Something not included in this report but reported by local media is that the first stylist visited an urgent care when she initially showed symptoms and was misdiagnosed as having allergies, and cleared to work. She was later found to be positive, and she infected the second stylist.

Masks Against COVID-19: An Evidence Review

Non-peer reviewed preprint, available online May 13, 2020

Masks are found to be effective in preventing the transmission of COVID-19. Fabric masks are recommended in order to keep surgical masks available for healthcare workers.  

Virus RNA was found in exhaled and cough droplets and aerosols, but was significantly reduced when the participant was wearing a surgical facemask. Originally published April 3, 2020 with a slight correction (words were swapped in a sentence that did not effect the conclusions) published on May 27, 2020.

The Missouri Commission for the Deaf and Hard of Hearing is producing masks for interpreters who need their mouths to be seen. Free of charge if you live in Missouri.

From 2014, NIOSH (the research equivalent of OSHA) studied the efficacy of face shields protecting health care workers against droplets and aerosols. In this short video, one of the study authors describes how face shields can be very effective for large droplets, but not as effective for aerosols that can swirl in the air and flow around the face shield.



Interview with Dr. Emily Smith, Friendly Neighbor Epidemiologist, with the Truett Church Network on November 19, 2020. In this discussion she talks specifically about why loving our neighbors means going above and beyond what is required, and takes a look at the current COVID surge from an epidemiological standpoint. An excellent interview.

An excellent interview with Dr. Shelly Miller from UC Boulder regarding indoor air quality and filtration. Broadcast on July 15, 2020.

Schlieren test showing a speaker reciting the alphabet.


From the L.A. Times, scientists are urging the WHO to agree with their assertion that SARS-CoV-2 can be spread by airborne means. Published July 4, 2020.

Podcast: "Connection: The Future of Choirs and Singing During the Pandemic" released June 25, 2020. Not a lot of new information here, but more experiences of how others have dealt with the changes that have come about during this time. I particularly appreciate the perspective that online choirs is not a replacement, but an expansion. At 35:12 a callr gives her experience of being five weeks into recovery from COVID-19.

Dr. Linsey Marr from Virgina Tech talks about aerosol and virus transmission with NYT science journalist Tara Parker-Pope. Note in particular the segment beginning at minute 34 discussing singing in particular. Broadcast June 15, 2020.

My own personal laryngologist, Dr. Lee Reussner in Lawrence, Kansas, has made a wonderful series of videos. This first one published May 14, 2020 talks about the overall issue, and would be a good, brief introduction to anybody who needs just a skim over the facts to get acquainted with our current predicament.

Part 2 published May 18, 2020, is longer and Dr. Reussner answers questions that have been submitted to him. There is a great bibliography in the video description. Check out the following time stamps for particular issues:


1:00-8:00--review of data and how we currently think the disease is spread (mainly through droplets, though aerosol is still a plausible consideration)

8:00-11:20--breathing, speaking, singing, sneezing and particle spread (note 9:17 for a new study on speaking and particle spread)

11:20-12:06--Likelihood of infection equals exposure multiplied by time

12:06-13:34--some evidence of aerosol transmission and the implications it may have for churches and choirs

13:34-16:37--how long the virus lives on surfaces like music, music stands, choir robes, etc.


What Do Science and Data Say About the Near Future of Singing?

Webinar hosted by NATS, ACDA, PAMA, Barbershop Harmony Society, and Chorus America on May 5, 2020

Micro droplets suspending in air

What Other Churches Are Doing

Not a church, but the West Point Music Research Center released their rehearsal protocols for the Army Band on June 3, 2020.  A PDF at the top of the article highlights their plexiglass protections.

Michigan UMC

A well thought out guide to resuming worship by an ecumenical group of clergy and lay leaders, focused mostly on liturgical worship settings. Singing is addressed specifically on page 19.

Wisconsin Council of Churches PDF on Church Music, published May 8, 2020


From the Guardian, a closer look at how choral groups have maintained the ability to sing together, even while apart during the pandemic. Published online April 21, 2021.


A brief overview of aerosol research in 2020 published by NPR on December 26, 2020.


A very practical summary of how to protect ourselves against aerosol transmission, published October 1, 2020 in Scientific American. The last paragraph sums it up nicely.


Published in Nature on October 6, 2020, an overview of the data on facemasks, which has evolved over the course of the pandemic.


Written by aerosol researcher Dr. Jose Luis Jiminez, a concise and compelling argument for why aerosol transmission should be considered in mitigation efforts. Published August 25, 2020.


A news article briefly announcing preliminary results from the CU Boulder study. Published July 17, 2020.

An invited commentary published in Clinical Infectious Diseases on July 6, 2020, "It Is Time to Address Airborne Transmission of COVID-19" by Donald Milton and Lidia Morawska.

Scientists in England are studying the "spittle" produced by choristers in church. A release date of data is not given, and they quote the flawed study from Munich, but it is interesting to note that this work is being done. Congregational and choral singing has been restricted as UK churches are allowed to open to in-person services beginning July 4, 2020. This article was published Sunday, June 28, 2020.

A letter to the editor of the Journal of Nanotoxicology references prolonged gatherings, especially those that involve speaking, chanting, singing, and heavy breathing, that seem to indicate a need to study aerosolization of particles and how those particles behave in various environments. Of note, "The airborne route becomes important when being for a prolonged time in the same room as a virus carrier, especially if that person is singing, shouting or physically active, as seen during superspreading events in choirs (Hamner et al. 2020) and fitness centers (Jang, Han, and Rhee 2020) and having a high viral load in the lining liquid (Riediker and Tsai 2020)."

From the Gospel Coalition author Ken Boer, "Is Congregational Singing Dangerous?" Published online May 7, 2020.


An infectious disease expert lists common activities and discusses their relative risk. Religious services are ranked as "high risk."

Church blogger Ken Braddy posed 24 questions you should ask before opening your church. Published April 18, 2020.

Helpful Ministry Resources

A view about when churches should gather from Dr. Daniel Chin, a pulmonary and critical care physician with training in epidemiology. Risk assessment tools. The top on in the list is especially helpful for churches. Plug in data, such as the square footage of the room and the number of people present, and get an estimate of risk.

Need some ideas for helping your congregation to adopt new safety protocols? This expert consensus statement from the National Academy of Sciences gives some bullet point ideas, as well as the rationale behind the suggestions.


Not specifically aimed at churches, but lots of helpful information. From the Harvard T.H. Chan School of Public Health, this Healthy Buildings publication is meant for schools to reopen safely. Several topics are discussed and this page with its guidelines is regularly updated.

This podcast tackles leading in our current times. I find the last section, starting around 31:30, to be particularly helpful. This podcast is from ministry leaders in Minneapolis, so they address they're local ministry opportunities with the events after the death of George Floyd as well as the COVID pandemic.

This document is a bit technical, but it is a risk estimator developed by aerosol researchers and environmnetal engineers at the University of Colorado. You need to know the volume of the room you will be in, and the air change rate for your HVAC system in order to use the estimator. Choose "Make a Copy" to save a copy directly to your computer that you can use.*qHPVlTHFJmiiEd0uIM0Tqg#gid=519189277

The CDC Reopening Guidelines for Faith-based Organizations

The CDC guidelines for reopening schools. While this doesn't necessarily pertain to churches, the guidelines could be a helpful guide for how to work with larger groups, and with children's programs.

Webinar archive from NCCO with ideas for continuing choral music online. It's mostly from a collegiate perspective, but may have some ideas for churches.

NATS COVID Resource Page

Includes links to webinars, financial resources, best practices, etc. Updated regularly.

I found this podcast helpful and encouraging: COVID-19 and Calling.

Likewise, the next episode deals specifically with working with teams.

I think there's a lot of truth here when thinking about the hardships of ministering in this time. There's a lot of links to resources at the end of the blog.

Some excellent ideas for church music ministries on the "Church Musician's Assistant" blog. It's being updated regularly.

Several sources for choosing music during this time, in addition to links to various other resource pages.

Additional Issues/Considerations

Rice University recently looked at aerosol production for various instruments and singers. Interestingly, aerosols tended to rise above the performers and mixing with air currents produced by ventilation systems. The recommendations at the end of the article are very good to read carefully.


Ten different wind and brass instruments were studied to determine aerosol production and distribution through the air. It was found that aerosols generally dissipated about a foot from the instruments. Trumpets produced the most aerosols, while tubas produced the least past the bell. Published September 16, 2020.


The New York Times surveyed 511 epidemiologists (not a peer-reviewed study, just an informal survey) about when they might return to 20 normal group or public activities. The responses were broken down into rough increments, starting with this summer, 3-12 months from now, over 1 year, and never again. There was some space left for nuance, as reflected in the comments included toward the end of the article. Generally speaking, when analyzing risk tolerance for certain things, mental health and overall emotional wellness can play a factor in determining whether an activity is important enough to risk it. Published online June 8, 2020.

NCVS writers and researchers suggest turning off ambient noise, including music in restaurants and stores. Because of the Lombard Effect, ambient noise can make people speak louder without realizing it. Churches may want to consider this when thinking about pre- and post-service music when people are more likely to converse.

A collection of articles that address some legal issues surrounding reopening.

Chorolosophy Podcast Episode 36: Are we asking all the right COVID questions? Chris Munce, a Kansas City area choral director, interviewed an infectious disease doctor practicing at Research Medical Center in KCMO. Munce is a school director, and so his focus has been on school choirs and appropriate risk analysis for planning for the upcoming school year. This is a long episode, but I've given some rough time stamps below. The sound quality is a bit poor in spots. I found it a little easier from my computer speakers than from my earbuds.


5:54-17:45--Dr. McKinsey discusses some of the basics of COVID-19, including a discussion of mortality rates and CDC stats

17:45-24:39--new information as of early June. OF NOTE: at age 50 the risk of poor outcomes increases, and at age 65 the risk increases again; also current thought is that an infected person will infect an average of 2.1 other people

24:39-32:40--the process of scientific discovery, and why there is confusion and disagreement

32:40---how we can use the information we have to determine our risk

Heather in the Media

Interview with Australia Broadcasting Company "The Drum" May 11, 2020

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