top of page

Hospital News vis-à-vis Air Filtration: The Importance of Air Filtration in Hospitals … during COVID

From HEPA Filters to ULPA Filters to Nanoparticle Air Filtration Systems

Mitigation is the Key … Some Potential Funding Leads as Well


During the initial outbreak of COVID in the U.S. and Europe, it was still uncertain how the virus was transmitted in certain and specified indoor environments. For the purpose of maximum protection—and out of an abundance of caution—all relevant safeguards were taken at that time, and rightfully so. The old adage applied, of course: Better safe than sorry. However, and as we gained a more comprehensive understanding of the virus and its variants, we began to review different methodologies being used inside of hospital environments. Analogous to hospital-borne bacteria, diseases, and other pathogens such as MRSA and C. diff, we now understand that the appropriate “cleaning” of those environments is indeed imperative—if not indispensable. One way in which to do this is through the changing and purification of air within the closed settings, including through enhanced air filtration systems.

When understanding the MRSA problem for a moment, we can look to this information as a backdrop and as a basis for comparison purposes:

There is growing concern about the presence of Methicillin-resistant Staphylococcus Aureus (MRSA), a type of bacteria that is resistant to most antibiotics. These bacteria used to be found mainly in medical facilities and nursing homes, but in recent years they have also been found in gyms, schools, sports clubs, and other places where people are in close contact.


From this information we garner the following:

a. Some types/strains of MRSA are resistant to most antibiotics.

b. They can be found “mainly in medical facilities and nursing homes;” and

c. They have been discovered in gyms, schools, sports clubs, and other places where people gather.

As a result, “cleansing” the air via enhanced air filtration devices and systems is an imperative and fundamental feature when it comes to preventing the spread of bacteria, viruses, and other pathogens.

Photo Source:

Of course, air filtration and “air changes” are not the only line of defense when it comes to protecting healthcare environments and other related areas. There are also “safe sprays” for surfaces, counters, beds, and other areas. Those sprays include an array of hypochlorous acid products, sometimes referred to as electrolyzed pH balanced salt-water compounds or HOCL. These are especially efficacious when applied via an electrostatic sprayer. Nonetheless, overall air filtration seems to be another primary and necessary element in our overall mitigation strategy to prevent and/or minimize the spread of infectious diseases, viruses, bacteria, and other harmful pathogens that could be airborne and/or could survive on surface environments.

According to a personal interview with Mitch Waldberg, the CEO of MGES, a leading company in the provision of engineered solutions for air filtration systems, on March 25, 2022, he says:

The optimal air change in an environment is specifically dependent on the use of the space. For example, if you’re dealing with an elementary school where you have 15 children in one classroom, between two and four air changes per hour—and possibly more—is ideal and would be sufficient. When it comes to hospitals and specifically with respect to waiting rooms where there is considerable congestion, our recommendation would be an air change of about six time per hour.

Then, industry leader, ASHRAE, says this as well:

The ASHRAE 62.1 (“Ventilation and Acceptable Indoor Air Quality in Residential Buildings”) recommends …
For other spaces like offices, shops, and schools, the ASHRAE 62.1 standard doesn’t give a fixed number. Instead, airflow rates are based on the size of a room, its use (e.g. school, office, sports arena), and the number of people inside. These can be used to calculate exact airflow requirements for a certain space.


So, when it comes to assessment and engineering, it is critical to calculate specific and exact airflow based the size of any given room.

We know that there is ample and sufficient medical data that tell us what we should be doing in this regard. According to MedRXiv:

… removing SARS-CoV-2 from the air of repurposed ‘surge’ wards and suggest that air filtration devices may help reduce the risk of hospital-acquired SARS-CoV-2.


At the peril of sounding too technical, let us just notice the level of study that has been performed in this regard:

Removal of SARS-CoV-2 by air filtration on surge ward
For the duration of the study … the beds in the ward and ICU were at 100% occupancy, with 15 patients admitted to the ward and 14 admitted to the ICU over the three-week sampling period (7, 4, 4 in weeks 1-3 in the ward and 6, 5, 3 in the ICU, respectively).
All patients were symptomatic and tested positive for SARS-CoV-2 RNA from a respiratory sample before admission.
Patients in the ICU were managed with non-invasive mask ventilation, high flow nasal oxygen or invasive ventilation via endotracheal tube or tracheostomy. Patients in the ward were spontaneously ventilating with simple oxygen therapy or no respiratory support and no aerosol-generating procedures performed.
In the ward, during the first week whilst the air filter was inactive, we were able to detect SARS-CoV-2 on all five sampling days; RNA was detected in both the medium (1-4μM particle size) and the large (>4μM particle size) particulate fractions (Fig. 2A). SARS-CoV-2 RNA was not detected in the small (<1μM) particulate filter.
The air filter was switched on in week two and run continuously; we were unable to detect SARS-CoV-2 RNA in any of the sampling fractions on any of the five testing days.
These initial observations provided evidence for the removal of SARS-CoV-2 via the air filter system, albeit at high baseline CT values. To confirm this observation, we completed the study by repeating the sampling with an inactive air filter.


In my mind, the crux of this is to clearly and decisively stress the following point:

The air filter was switched on in week two and run continuously; we were unable to detect SARS-CoV-2 RNA in any of the sampling fractions on any of the five testing days

Source: Ibid.

Again, according to Mitch Waldberg, the CEO of MGES, LLC:

It is not sufficient to speak solely of HEPA filters and air handlers alone. We are talking about additional air changes in rooms; that is critical. In some cases, HEPA filters do not filter out the fine elements of COVID. Also, these filters can even restrict air flow, thereby reducing air changes. HEPA filters remove the heavier particles from the air, but not the smaller micro particles.

We should keep in mind that the EPA clearly states that HEPA filters only “theoretically” remove harmful and dangerous “airborne particles”:

HEPA is a type of pleated mechanical air filter. It is an acronym for "high efficiency particulate air [filter]" (as officially defined by the U.S. Dept. of Energy). This type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (µm). The diameter specification of 0.3 microns responds to the worst case; the most penetrating particle size (MPPS). Particles that are larger or smaller are trapped with even higher efficiency. Using the worst case particle size results in the worst case efficiency rating (i.e. 99.97% or better for all particle sizes).
Minimum Efficiency Reporting Values, or MERVs, report a filter's ability to capture larger particles between 0.3 and 10 microns (µm).


Operating the air filter helped to eradicate the environment of SARS-CoV-2 RNA in this specific hospital setting. At the same time, the air filtration unit can do much, much more. That is why it is important to identify, select, and install the appropriate air filtration units in hospitals and other healthcare environments—sooner rather than later.

When conducting more research, our team noticed that at least one notable journal, Environmental Science & Technology (by citing the CDC), has also weighed in on the topic with specificity:

The prevention of healthcare associated infections (HAIs) has long been a top strategic priority for the Center for Disease Control and Prevention (CDC).
(1) Still, an estimated 90,000 deaths occur per year in the United States.
(2) The recent pandemic manifested an urgent need to better understand and implement design, maintenance, and operations that ensure indoor air quality in healthcare facilities.
Specifically for the SARS-CoV-2 virus, the CDC recognizes … the airborne transmission via small particle aerosols containing viable virus.


At the risk of being repetitive and redundant, this is a key feature:

The recent pandemic manifested an urgent need to better understand and implement design, maintenance, and operations that ensure indoor air quality in healthcare facilities.

Source: Ibid.

Additionally, there is an actual scientific formula when it comes to understanding air flow. In light of that, we may wish to consider the following:

Taking the room as a large control volume, one could derive the differential equation

(1)where V is the volume of the room, C is contaminant concentration as a function of time, Csis contaminant concentration at the supply air inlet, Qs and Qr are supply and return flow rates, and S is a source of contamination in the room (Figure 1). Without a loss of generality, let us assume that the supply and return flow rates are identical, Qs = Qr = Q. It is noteworthy that for pressurized spaces (i.e., operating rooms (OR), AIIRs) this assumption is not valid. In general, eq 1 is a linear differential equation with an exponential solution. For example, eq 1shows an exponential decay for a single release of contaminant. One can argue that the efficiency of the filter changes with time, which will turn eq 1 into a nonlinear problem that must be solved numerically. (22)


Source: Ibid

Added to this, the National Institutes of Health (NIH) tell us that:

The outbreak of SARS-CoV-2 has made us all think critically about hospital indoor air quality and the approaches to remove, dilute, and disinfect pathogenic organisms from the hospital environment.


Then, the American Society for Healthcare Engineering (ASHE) says this:

Appropriate air filters should be used and maintained within HVAC systems, biological safety cabinets, horizontal laminar flow benches, and pathology workstations. Filters are selected based on the type of contaminants they are designed to trap. Filters … are usually designed to trap particulates. In spe­cial exhaust systems and fume hoods, filters may be installed to trap gases, vapors, and particulates. Filters within biological safety cabinets and horizontal laminar flow benches are designed to trap fumes, mists, and particulates. Filters in pathology workstations are usually designed to trap formaldehyde vapors.


What do Medical Doctors Say?

In an interview with a notable doctor who has practiced for over 30 years as a chief emergency room physician (and most recently at Barnes Jewish Hospital in St. Louis), he reminded us of the following when considering air filtration in hospital emergency rooms and related waiting areas:

We should note that there are now advanced filters called “ULPA Filters,” that have some merit; those filters feature 0.1 microns openings.
SARS-Cov-2 is technically .06 to 0.14 microns in size. But the virus is never “naked” and is usually attached to proteinaceous material or mucous.
Additionally, N95 facemasks only cover about 95% of possible pathogens as well.

The online journal—Pharmaceutical Guidelines—tells us this about the difference between HEPA filters and ULPA Filters:

HEPA filters can remove up to 99.97% of contaminants as small as 0.3 microns in diameter, ULPA filters can remove 99.99% of the particulates that are 0.12 microns or more in diameter.


Potential Funding

As we might imagine, many healthcare entities are wondering whether any of this (or all of this) may be paid for through the CARES Act or similar. Obviously, CARES Act funding was and continues to be available primarily to healthcare institutions, hospitals and the like. However, specific “set asides” for air filtration are more difficult to understand.

One entity tells us this specifically:

The Coronavirus Aid, Relief, and Economic Security (CARES) Act of 2020 and the Coronavirus Response and Relief Supplemental Appropriations Act of 2021 (CRRSAA) are designed to provide rapid and direct economic support for American workers, families and small businesses while preserving jobs for American industries.
Healthcare: The legislation could help large health care facilities cover indoor air quality technology that helps prevent, prepare for and respond to challenges related to COVID-19.


In recent days there have been questions regarding what may be eligible for reimbursement under the Public Health and Social Services Emergency Fund (CARES Act) due to the COVID-19 pandemic.

Under the guidelines of the CARES Act, increased funding of the Public Health and Social Services Emergency Fund, an organization must use the funds “to prevent, prepare for, and respond to coronavirus, and the payment shall reimburse the recipient only for healthcare-related expenses or loss of revenues that are attributed to coronavirus.”

Having said that (and according to a few medical doctors we spoke with about this), we were told:

Many—if not most—hospitals and hospital systems have educational tie-ins. As a result, hospitals should be able to qualify for some sort of “educational funding” related to air filtration.

We then followed up and discovered the following about those sorts of funds:

Governor’s Emergency Educational Relief FundCongress set aside approximately $3 billion of the $30.75 billion allotted to the Education Stabilization Fund through the CARES Act for the Governor’s Emergency Education Relief Fund (GEERF). The Department will award these grants ­to States (governor’s offices) based on a formula stipulated in the legislation. (1) 60% on the basis of the State’s relative population of individuals aged 5 through 24. (2) 40% on the basis of the State’s relative number of children counted under section 1124(c) of the Elementary and Secondary Education Act of 1965 (ESEA).
January 8, 2021 – GEER II The Coronavirus Response and Relief Supplemental Appropriations Act, 2021 (CRRSA), was signed into law on December 27, 2020 and provides an additional $4,053,060,000 for the Governor’s Emergency Education Relief (GEER) Fund.
The CRRSA Act … provides that $1,303,060,000 of those funds be used to supplement the Governor’s Emergency Education Relief Fund (GEER II Fund) awarded to each State with an approved GEER application under the Coronavirus Aid, Relief, and Economic Security (CARES) Act enacted on March 27, 2020.


Emergency Assistance to Non-Public Schools
The Coronavirus Response and Relief Supplemental Appropriations Act, 2021 (CRRSA Act) provides $2.75 billion for the Emergency Assistance to Non-Public Schools (EANS) program, which is part of the Governor’s Emergency Education Relief Fund. Under the EANS program, the Department will award grants by formula to each Governor with an approved Certification and Agreement to provide services or assistance to eligible non-public schools to address the impact that the Coronavirus Disease 2019 (COVID-19) has had, and continues to have, on non-public school students and teachers in the State. The deadline for submission of the signed Certification and Agreement is February 22, 2021. Please see the Awards page for information about the award date, amount and the approved Certification and Agreement for each State.


An email contact for EANS funds is as follows:

An email contact for GEER funds is:

* * * * *

Ultimately, improving air flow in hospitals and other healthcare environments is of fundamental importance and significance. Clean air—especially in crowded indoor areas such as hospital emergency rooms—is imperative to protect against the spread of COVID-19, its variants, and other pathogens. It is “high-time” to get a detailed assessment of your facility, as well as an in-depth indoor engineering analysis to determine the appropriate path to mitigate the damage that can be done by airborne particles and other harmful pathogens.

bottom of page