Coronavirus Technology Solutions
August 5, 2020
Will HVAC Filters Act as Aerosol Generators for Cough and Sneeze Droplets?
Some Virus Particles will Penetrate Even HEPA Filters
Tyler Smith Interview on Safe Buildings
School Reopening was the Wrong Choice in Israel
U.S. can Learn from School Openings Around the World
School Closings are a Generational Catastrophe
Many Schools have Reopening Problems
Schools Need Major Investments in HVAC in Order to Reopen More Safely
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Will HVAC Filters Act as Aerosol Generators for Cough and Sneeze Droplets?
If a person sneezes and emits large droplets which are captured in an HVAC system they will likely be captured on the filter. But it would seem that the same aerosol generation phenomenon will occur in the filter as we now believe occurs in masks. The droplet will evaporate releasing small aerosols. These aerosols will then penetrate the filter and be released back into the environment
There are lots of general studies showing re emission of microorganisms from HVAC systems.
“Currently, most indoor air-conditioning systems contain internal filters that extract microorganisms from the air. However, these microbes often remain viable and can be returned to the surrounding atmosphere under certain circumstances, such as inefficient operation, during periods of maintenance, or due to temporary malfunction.
[https://www.intechopen.com/books/low-temperature-technologies/impact-of-air-conditioning-filters-on-microbial-growth-and-indoor-air-pollution
There have been a number of studies showing the benefits of UV light directed on the surface of filters for the purpose of preventing growth and penetration.
“The EnviroKlenz UV System solves the dosage problems by placing the UV-C light before the HEPA filter which captures biological contaminants 0.3 microns and larger. The droplet size from coughing or sneezing humans is very broad, and a HEPA filter can capture the bulk of that particulate matter range. Integrating UV lamps within the air purification device allows for continual bathing of the collection site of the HEPA filter, which allows for the items collected on the surface of the HEPA filter to get a lengthened or even infinite residence time. In the EnviroKlenz Mobile Air System with UV lights, the pathogens are exposed to the UV-C light as long as the unit and its lights remain on in the air purification system.”
This assumes that the sneeze droplet stays on the filter long enough for the UV to kill it. But if it quickly evaporates that still should not be a problem if the filter is HEPA grade. But if it is a MERV 13 filter or lower then it is logical to assume that the viruses pass through.
The challenge for HVAC filters is much greater if people wear cloth masks and generate small aerosols. Schools are reopening with everyone wearing cloth masks. Isn’t it logical to assume that the HVAC systems will be loaded with small aerosols caused by the selection of inefficient masks. Lots of lives will be saved if the filter rating in the HVAC system is upgraded to MERV 16 or higher. On the other hand if students wear N95 masks the problem will be minimized.
Some Virus Particles will Penetrate Even HEPA Filters
A 10 year old study is relevant today with its findings about penetration of viruses through HEPA filters. High Efficiency Particulate Air (HEPA) filters are the primary technology used for particulate removal in individual and collective protection applications. HEPA filters are commonly thought to be impenetrable, but in fact they are only 99.97% efficient at collecting the most-penetrating particle (approx. 0.3 micrometer).
While this is an impressive collection efficiency, HEPA filters may not provide adequate protection for all threats: viruses are submicron in size and have small minimum infections doses (MID50). Thus, an appropriate viral challenge may yield penetration that will lead to infection of personnel. However, the overall particle size (agglomerated viruses and/or viruses attached to inert carriers) will determine the capture efficiency of the HEPA filter. Aerosolized viruses are commonly thought to exist as agglomerates, which would increase the particle size and consequently increase their capture efficiency.
However, many of the threat agent viruses can be highly agglomerated and still exist as submicron particles. We have demonstrated that MS2 coli phage aerosols can penetrate Carbon HEPA Aerosol Canisters (CHAC). At a face velocity of 2 cm/sec, a nebulized challenge of approx. 105 viable plaque forming units (PFU) per liter of air results in penetration of approx. 1 - 2 viable PFU per liter of air. We are currently investigating the particle size distribution of the MS2 coli phage aerosol to determine if the challenge is tactically relevant. Preliminary results indicate that 200-300-nanometer particles account for approx. 7.5% of the total number of particles. Our aim is to characterize multiple aerosol conditions and measure the effects on viable penetration. This study will expand our knowledge of the tactical threat posed by viral aerosols to HEPA filter systems
Tyler Smith Interview on Safe Buildings
McIlvaine is continuing its recorded expert interviews. Yesterday we had an extensive discussion with Tyler Smith who started with York which became part of Johnson Controls.
Tyler Smith
General Manager - Controls Specialty Products at Johnson Controls
The scope of his activities for Control Specialty Products includes
§ Laboratory and healthcare controls
§ Control panels
§ Airflow control
§ Energy control and monitoring
§ Air Quality Collaboration Among subsidiaries
McIlvaine asked Tyler about the world wide scope of the COVID activities and referenced the April 29 CTS where the rapid response of Johnson Controls had allowed a new hospital in Wuhan to be be quickly operational with the controls and isolation room air purifiers which were necessary.
Tyler cited this as an example of the world-wide reach and the ability to quickly deliver in an emergency. Later on in the interview Tyler introduced the subject of schools in the U.S. which are now trying to open but in many ways are experiencing the same level of urgency and need the Wuhan hospitals did in January.
Tyler cited the value of focusing on those who are speaking and therefore potentially generating more virus than others. This differs by grade level. Johnson Controls has room air purifiers which can be an immediate solution. ENVIRCO fan filter units are another option for obtaining HEPA filtered downflow air economically covering a space. This is in addition to the following:
- HVAC filters: MERV 13 filters have been found to be of sufficient efficiency for many applications. However, through its Koch Filter division Johnson Controls offers higher efficiency filters through HEPA.
- York Air Handling Units: To reduce airborne pathogens within a building, mixed-air HVAC systems should focus on increasing outdoor air ventilation. York air handling units allow customers to maximize outside air to displace contaminated air and increase ventilation and air change rates.
- Critical Environment Controls: Room pressurization, air change rates, humidity, and temperature are equally as important components in reducing airborne contaminants and preventing cross contamination within schools and buildings as they once were just for the healthcare and laboratory facilities. The Johnson Controls line of Critical Environment Controls includes the broadest suite of products in the industry.
- UV-C Lighting: Disinfectant lighting solutions are necessary to reduce pathogens both on surfaces and in the air. Johnson Controls offers a comprehensive suite of disinfecting lighting products, including retrofit options to keep facility disruptions and installation costs to a minimum. Bipolar ionization is another technology which is being evaluated presently.
By integrating HVAC, lighting and security systems into a single digital platform like Johnson Controls Metasys® building automation system, building owners and operators can easily troubleshoot issues and implement system changes.
Tyler pointed out that the system can provide the right balance between energy consumption and safety. In areas with higher virus loads more efficient filters can be utilized and the number of air changes can be increased. More outside air can be used to dilute the virus load. But this brings up the subject of the contaminant burden in outside vs indoor air. In polluted areas the particulate load from outside air will be significant.
The advantage which schools and building owners experience with Johnson Controls is the local assistance from 120 branch locations in North America with 13,600 field technicians and mechanics.
You can view the interview at: https://youtu.be/6D-bu3MZ5bQ
School Reopening was the Wrong Choice in Israel
As the United States and other countries anxiously consider how to reopen schools, Israel, one of the first countries to do so, illustrates the dangers of moving too precipitously.
Confident it had beaten the coronavirus and desperate to reboot a devastated economy, the Israeli government invited the entire student body back in late May. Within days, infections were reported at a Jerusalem high school, which quickly mushroomed into the largest outbreak in a single school in Israel, possibly the world.
The virus rippled out to the students’ homes and then to other schools and neighborhoods, ultimately infecting hundreds of students, teachers and relatives. Other outbreaks forced hundreds of schools to close. Across the country, tens of thousands of students and teachers were quarantined.
Israel’s advice for other countries “They definitely should not do what we have done,” said Eli Waxman, a professor at the Weizmann Institute of Science and chairman of the team advising Israel’s National Security Council on the pandemic. “It was a major failure.”
The lesson, experts say, is that even communities that have gotten the spread of the virus under control need to take strict precautions when reopening schools. Smaller classes, mask wearing, keeping desks six feet apart and providing adequate ventilation, they say, are likely to be crucial until a vaccine is available.
“If there is a low number of cases, there is an illusion that the disease is over,” said Dr. Hagai Levine, a professor of epidemiology.
The United States is facing similar pressures to fully reopen schools, and President Trump has threatened to withhold funding for districts that don’t reopen. But the U.S. is in a far worse position than Israel was in May: Israel had fewer than 100 new infections a day then. The U.S. is now averaging more than 60,000 new cases a day, and some states continue to set alarming records.
https://www.nytimes.com/2020/08/04/world/middleeast/coronavirus-israel-schools-reopen.html
U.S. can Learn from School Openings Around the World
One large new study from South Korea found children under the age of 10 appear to not transmit the virus very well. While it's not exactly clear why, the pediatric infectious disease experts contacted by WIRED say that it's perhaps because young children expel less air that contains the virus and are shorter, so any potential respiratory droplets are less likely to reach adults. A study published in April by researchers at the Brigham and Women’s Hospital in Boston suggests that younger kids haven’t developed the molecular keys that the virus exploits to enter the body and wreak havoc on the respiratory system, microscopic structures known as ACE2 receptors.
But older students are more like adults in their ability to transmit the virus, according to the South Korea study, which makes school opening decisions tougher. Should administrators allow only elementary students to attend in person, while middle and high schoolers stay online at home? If they do, will younger children be able to keep their masks on all day or stay six feet apart? What about the psychological effects of continued isolation on teens, who many parents believe are already racking up too much screen time during the pandemic shutdown and now are facing months of online learning?
The CDC announced school reopening guidelines that call for officials to reopen classrooms this fall, based on the idea that children do not become as sick from Covid-19 and are less likely to spread it as adults, and to belay any emotional and psychological harm from the disruption of schools staying closed. The agency issued these new guidelines after President Donald Trump attacked initial rules that called for desks being set 6 feet apart, staggered lunches, and temperature screenings, as being too costly and burdensome.
Dimitri Christakis helped draft a separate set of reopening guidelines for US schools in a report for the National Academy of Sciences released July 15. It says schools should take steps to reopen for younger students in grades K-5 and those of all ages who have special needs. Christakis says that with appropriate social distancing, hand-washing and protective masking, the risk to teachers, staff and students in a school can be reduced.
“With those additional precautions, primary school teachers should feel comfortable going to school,” says Christakis, director of the Center for Child Health, Behavior and Development at Seattle Children's Research Institute. “Those are the kids for which in-person learning is so important. We should prioritize these kids.”
At the same time, Christakis admits there are still some unknowns about transmission among school-age children. “We don’t have the answer to what extent children transmit the virus in general, and in particular in a school setting,” he says. “This is called the ‘novel coronavirus’ for good reason. It is acting very differently than most respiratory viruses and many other coronaviruses. Children appear to be less affected directly, and potentially less likely to transmit.”
Physicians like Christakis have been following the publication of epidemiological studies around the world to help make decisions about what might happen when schools might reopen in the US. Some countries, like Norway and Denmark, reopened their schools in the late spring starting with younger students. Schools there boosted sanitizing procedures and limited class size, keeping children in small groups at recess and putting space between desks. With these practices in place, neither country saw a rise in cases after reopening schools in April and May, according to a report on worldwide school practices compiled by the University of Washington Department of Global Health earlier this month.
School Closings are a Generational Catastrophe
United Nations Secretary General Antonio Guterres warned Tuesday that the world faces a “generational catastrophe” because so many schools have been closed because of the coronavirus pandemic.
“The COVID-19 pandemic has led to the largest disruption of education ever,” the U.N. chief said.
One billion students were left without classrooms when schools were closed in 160 countries across the globe and 40 million children “missed out on education in their critical pre-school year,” he said.
Now we face a generational catastrophe that could waste untold human potential, undermine decades of progress, and exacerbate entrenched inequalities,” Gutteres said. “Getting students back into schools and learning institutions as safely as possible must be a top priority.”
In the U.S., the question of how and when schools should reopen has pitted politicians versus parents versus teachers while President Donald Trump has pushed for a rapid reopening of schools even as the grim arithmetic scoffs at his prediction that the pandemic would “just disappear.”
Trump on Tuesday suggested Democrats want to keep the economy hobbled and schools closed for political rather than safety reasons.
"Frankly, they want to keep it closed, I think, as long as possible," he told Fox News' Lou Dobbs. "Maybe for some good reasons but maybe also for political reasons. But we want it opened. We want the schools open, Lou. You know, young people have better immune systems than we do, Lou."
But now the U.S. is closing in on 5 million confirmed COVID-19 cases and 156,000 deaths, both world-leading numbers, according to the latest NBC News tally. And the president has had to acknowledge that reality.
“They are dying, that’s true,” Trump said of the exploding death rate in an interview recorded last week with Axios’ Jonathan Swan. “And you have — it is what it is.”
Arizona, Alabama, Florida, Mississippi and Louisiana -- all (except Louisiana) states led by Republican governors loyal to Trump that reopened before local health officials could flatten the coronavirus curve -- have seen the biggest increases in the number of new cases over the last two weeks when adjusting for population, NBC News has calculated.
Many Schools have Reopening Problems
On Wednesday, teachers in Georgia’s largest school district returned to elementary, middle and high school campuses to start in-person planning for the fall semester.
By the next day, 260 district employees had been barred from entering their schools, either because they tested positive for the coronavirus or had been directly exposed to someone who had.
Sloan Roach, spokeswoman for Gwinnett County Public Schools, which serves more than 180,000 students, told the Atlanta Journal-Constitution that most of the cases were tied to community spread, rather than being spread at the schools. Some of the employees who reported exposure to the virus had not come to work yet, Roach added.
“Given the number of [covid-19] cases in Gwinnett, we would expect to see positives among our employees based on the community spread in our county,” Roach told the newspaper.
The outbreak has complicated the return to school in Gwinnett County, which this week had the highest number of new coronavirus cases in the state. Georgia has reported 195,435 cases and 3,842 deaths to date. But Gwinnett County’s teachers and school administrators are hardly alone in dealing with the fallout of an early outbreak as they try to launch a digital-only return.
Coronavirus infected at least 260 children and staffers at a sleep-away summer camp in Georgia last month, according to a report published by the Centers for Disease Control and Prevention last week.
Report: Coronavirus infected scores of children and staff at Georgia sleep-away camp
On Thursday, the first day back for students at a middle school in Greenfield, Ind., a student who came to classes tested positive.
Within the first week of reopening, a school district in Mississippi reported its first positive case and identified 14 other students who came in contact with the sick pupil. By Monday, two more students had tested positive, the district said on Facebook.
After attending a three-day retreat to plan the upcoming school year, 11 school leaders who serve campuses in Chanute, Kan., tested positive for the virus by Monday.
Across the nation, school districts have been struggling to find the safest, most effective way to return to class this fall. But spiking coronavirus case rates, particularly in the Midwest and South, where outbreaks have been growing rapidly in recent weeks, have complicated the reopening process.
Coronavirus cases are climbing in Midwest states with previously low infections
States and individual districts have adopted a patchwork of policies governing how schools should shut down when outbreaks spread through classrooms.
In Mississippi, the health department suggests closing a school if three classrooms, sports teams or clubs experience outbreaks at the same time. Schools in New York City will only reopen for in-person instruction if the city’s positive test rate remains lower than 3 percent, and if two students in different classrooms test positive, their school will shut down. California is allowing schools to reopen as long as their county hasn’t been on the state’s watch list for two weeks and will require schools to close only if more than 5 percent of students and staff test positive within a 14-day period.
Texas is forcing schools to reopen with at least some form of in-person instruction within two months of the state’s typical start date or risk forfeiting funds. Florida also required all of its schools to reopen classrooms this fall but will allow parents of students to opt for online learning if they want.
Georgia has left control over closures up to school districts.
As scores of employees at Gwinnett County Public Schools tested positive in the last week, hundreds of teachers reportedly reached out to the Atlanta Constitution-Journal to share their experiences during the first week back on campuses.
At least one teacher quit her job at Gwinnett Elementary School because she had no option to work from home, even though her district is starting the school year with virtual classes.
“Back in April teachers were considered heroes,” Ashley Newman told WAGA-TV after she decided to leave her job. “But that messaging has changed. Now if you’re not willing to risk your life by going into a building unnecessarily then you’re lazy.”
https://www.washingtonpost.com/nation/2020/08/04/school-outbreaks-reopening-georgia/
Schools Need Major Investments in HVAC in Order to Reopen More Safely
A federal watchdog estimates that 41 percent of school districts need to update or replace heating, ventilation, and air conditioning systems in at least half their schools, underscoring a significant infrastructure need for schools even as they prepare for the novel coronavirus when they reopen.
In a report published last week the Government Accountability Office said that several schools it visited had HVAC systems that leaked and caused damage, and that if not addressed, "such problems can lead to indoor air quality problems" and even force schools to temporarily close while the issues are fixed. In all, the GAO estimated that 36,000 schools need HVAC updates.
The GAO report does not deal directly with the specific challenges posed by COVID-19; the report says that the "hazardous conditions" it refers to that can lead to school closures don't include the virus.
However, while school infrastructure is regularly a focus of education legislation and lobbying on Capitol Hill, it could become more important during the pandemic. Last month, the Centers for Disease Control and Prevention released long-awaited guidance to help schools reopen, and among the recommendations is that schools should "ensure that ventilation systems operate properly" and should increase ventilation of outside air by opening windows and doors, unless it creates concerns for students with asthma.
The additional health measures schools are considering or might feel are necessary for the next school year, and how much they'll cost, will be a major issue this summer as education officials prepare for the 2020-21 school year. It's one reason why they say they need additional financial resources, even as state budgets take a hit due to the economic slowdown caused by the pandemic. The CDC guidance also touches on potentially difficult spots with respect to coronavirus-related safety protocols like water fountains.
Even before the COVID-19 pandemic, outdated and hazardous school buildings were undermining the quality of public education and putting students and educators at risk," said Rep. Bobby Scott, D-Va., the chairman of the House education committee, in a statement responding to the GAO report. "Now, the pandemic is exacerbating the consequences of our failure to make necessary investments in school infrastructure."
It's still unclear to what extent school-age children can and do transmit the coronavirus, although they have mostly escaped major health problems associated with COVID-19. However, older school staff and those with chronic health conditions, to say nothing of others they might come into contact with, are at higher risk of COVID complications.
In 2018, Sabrina Lee and Jake Varn wrote about school infrastructure for the Bipartisan Policy Center and stated that, "Importantly, low-income communities and communities of color have been, and continue to be, disproportionately affected by poor school conditions." And black people in particular have been hit hard by the coronavirus pandemic, according to the CDC.
The GAO found that the share of schools estimated to need major HVAC help, compared to the share needing significant upgrades for roofing and structural integrity, was the largest. The report also estimated that 21 percent of districts need key updates or replacements for "indoor air quality monitoring" in at least half their schools.
Remember that the CDC guidance we mentioned above recommends bringing in more outside air by opening windows and doors, in addition to ensuring that mechanical ventilation systems work well. Of course, in some schools, leaving windows and doors open for extended periods during the first few weeks of the school year could create an uncomfortably warm and humid environment for students, to say nothing of colder periods.
A recent article posted by the CDC about a coronavirus outbreak linked to a restaurant in China notes that "droplet transmission was prompted by air-conditioned ventilation." The piece recommended increasing distance between tables as well as "improving ventilation." The CDC guidance recommends spacing students' desk farther apart than normal, although that presents new challenges around classroom and school space.
In the case of the restaurant in China, the problem was that the air-conditioning system functioned poorly and just moved the virus around the room, rather than properly diluting and moving the air out of the room, said Rick Hermans, who's in charge of school issues on the COVID-19 task force at the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Yet schools often put off maintenance of HVAC systems that would address such problems, he said.
"There's always difficulty certainly in staffing the schools themselves with what we refer to as engineers, people who are responsible for operating the systems within the buildings," said Hermans.
Here's a portion of the GAO report that also highlights this issue:
"Officials in several school districts we visited said there are serious consequences to not maintaining or updating HVAC systems, including lost educational time due to school closings and the potential for mold and air quality issues ... For example, officials in a Michigan district said about 60 percent of their schools do not have air conditioning, and in 2019, some temporarily adjusted schedules due to extreme heat. Without air conditioning, schools relied on open windows and fans, which were not always effective at cooling buildings to safe temperatures for students and staff, according to district officials."
ASHRAE said in April that, "In general, disabling of heating, ventilating, and air-conditioning systems is not a recommended measure to reduce the transmission of the virus." And the group recently released a pandemic-focused guide for schools looking to reopen.
Among other things, that guide says to create a district-wide health and safety committee and develop policies for staff and contractor use of personal protective equipment, often referred to as PPE; the CDC guidance for school reopening mentioned above says all school staff should wear face coverings.
Hermans said that one temporary solution for schools is to buy portable HEPA filters and put them in classrooms to clean the air. However, he said, those devices can be noisy and distracting for students. And since a lot of classrooms don't have air conditioning, he noted, "In a lot of schools, the open window is the only cooling that classroom gets" and therefore can be helpful to a certain extent.
The GAO report said some schools prioritize safety infrastructure over other building systems. It highlighted one school in Florida that bought new security cameras, even as a faulty HVAC system required maintenance workers to go up to the roof every day to address it.
It's far from a sure thing that a new federal coronavirus relief package will include help for these areas. In early 2019, congressional Democrats introduced the Rebuild American Schools Act that would provide $100 billion for school infrastructure needs, including $70 billion in direct federal spending. However, that bill was not included in the coronavirus aid bill passed by the House last month.
