Improving Indoor Air Quality in Hospitals

IAQ is by far the most often ignored of the three ways to transmit disease in health care facilities (the other two being surfaces and human contact).

What does IAQ stand for? Indoor air quality. Doctors, infection prevention nurses, and maintenance & engineering department heads are slowly coming around to the idea that hospital air control is just as important as managing surface disinfection and human contact.

The answer to how to decrease infection rates in hospitals starts with recognizing the serious threat of airborne pathogens.

What Are Airborne Pathogens?

How is airborne disease transmitted in hospitals? Through airborne pathogens.

So many documents tell you what they are and what illnesses they cause, but few if any centralize all the crucial facts about health care-associated infection  (HAI) control in one place.
We’ve done that for you here.

Pathogens in the air are spread on particles or droplets. The solid matter may come from human skin scales, while the droplets may be generated from:

Upper and lower respiratory tract





Dripping water taps

Small respiratory droplets start to evaporate after release and then change their size, resulting in droplet nuclei that are sufficiently small to remain suspended in the air for long periods of time — and still be infectious.

Respiratory droplets can be spread by:






Artificial means of producing potentially infectious aerosols in hospitals include using respiratory assist equipment such as:



Oxygen masks

Survival of pathogens in the air depends on their amount of time in the air as well as ambient environmental factors, like temperature and humidity. The transport of airborne droplets is affected by:

Local ventilation air flows

Movement of people

Thermal gradients produced by various electrical equipment

Another factor is receptors in human host cells. Differing patterns of receptor distribution between different individuals in the upper and lower respiratory tracts will affect the ease with which inhaled airborne viruses can cause infection and disease.

The nature of the infecting agent and human respiratory activity itself may cause a different variety of pathogen to be expelled, with differing effects on secondary cases.

Coughing brings up deep-seated pathogens from the lower respiratory tract in the chest. These can include species of:







How Is Airborne Disease Being Transmitted In Hospitals?

One in 25 hospitalized patients are affected by a health care-associated infection, according to the U.S. Centers for Disease Control and Prevention (CDC).
Patients picked up 721,800 HAIs at U.S. acute care hospitals in 2011. Of those infected, about 75,000 died, according to the CDC.

Here are some examples of dangerous airborne pathogens your staff should be prepared to handle:


Airborne HAIs came more into focus with reports of deaths caused by mold clusters at two Pennsylvania hospitals.
Investigation showed heavy mold growth on the hospital linens being used.

Legionnaires’ Disease

Awareness of health care-association infections increased after a Legionnaires’ disease outbreak killed 12 people in the South Bronx.

Legionnaires’ disease doesn’t spread from person to person. Instead, the bacteria spreads  through mist, such as from air-conditioning units for large buildings.


Tuberculosis can be a source of outbreak in hospitals. Health care workers infected with TB can spread infection widely, requiring extensive screening of patients and staff.


Norovirus, transmitted through the air, is difficult to contain in a hospital ward without sufficient single rooms with en suite toilets. 

To ensure sufficient dilution of bacterial load around an infected patient room, air should be changed 10-20 times every hour. This is difficult to maintain with ventilation systems especially in negative pressure rooms. More on that below.


MRSA can survive on skin scales for up to 80 days, and spores of Clostridium difficile may last even longer. MRSA can travel in the air on these smaller skin scales for the length of a ward. Minimal colonization of these bacteria on open wounds and mucous membranes can cause significant infections

Hospital Indoor Air Quality Testing

If you haven’t been focusing on air disinfection at your health care facility, the above information may have you scrambling for a quick solution. It’s beneficial, though, to first talk about testing. Because one company’s claims may vary wildly from another’s in terms of perspective and testing methods.

Many air device efficacy claims are based on testing with:

Small bioaerosol chambers

Testing occurred in a very small test chamber or non-full-size room.

Non-independent academic labs

Testing happened in a non-EPA Guideline Testing Chamber Location/Laboratory.

Excessively long contact times

Pathogen contact time took multiple hours for an efficacy report.

Ineffective killing percentage rate

The air disinfection device claims an efficacy rate of 99%. This rate is simply not sufficient when hospital-grade disinfection is needed.


(or Lack Thereof) 

for Air Quality Testing in Hospitals

Indoor air quality continues to rise in importance as a public health issue in multiple industry sectors. Many of the regulations affecting indoor air quality are only recommended guidelines by federal and nonprofit regulatory groups. These guidelines are fragmented, incomplete and overlapping, but the federal government and states are working on drafting regulations.

The EPA has strict requirements regarding EPA registered chemicals, including Good Laboratory Practices for chemistry, toxicology, and efficacy of these chemicals.

Air management devices do not require EPA registration and therefore do not require strict formal testing of their efficacy claims. Air management devices are only “regulated “ by the EPA rather than registered. Regulated devices are not required to disclose their efficacy data or verify their efficacy claims in their marketing materials.

A Note on Ozone

The EPA has dispelled effectiveness claims made by air disinfection devices that involve photocatalytic oxidation and ozone production.  

Residential Vs. Hospital

The EPA does have a website on residential air cleaners. At this site they dispel the effectiveness claims of certain technologies such as photocatalytic oxidation. It is up to the consumer of these devices to carry out their due diligence on investigating efficacy claims in regards to particulate reduction, pathogen killing, and odor removal.

And remember, those air purification devices claiming 99% or even 99.9% reductions in pathogens are for houses, not hospitals. You can’t solve your airborne pathogen outbreak with a trip to Home Depot.

Airborne Pathogen Reduction in Hospitals

Here’s another real-life story about a hospital with an airborne pathogen crisis. 

Suspected mucormycetes mold clusters at a world-renowned heart transplant facility led to the deaths of three transplant patients. These deaths resulted in the closing of the facility’s cardiothoracic intensive care unit and shut down the transplant program for nearly a week. You can imagine the catastrophe this caused for current patients, incoming patients, patients’ families, and hospital staff.

A report from the U.S. Centers for Disease Control and Prevention pointed out ventilation systems in patients’ rooms as a possible transmission vehicle for the fungal infections.

The hospital started:

Using safe cleaning solutions to destroy bacteria, viruses, and spores

Deployed a robot that uses ultraviolet light to disinfect medical equipment as well as hospital and operating rooms

Also used the robot to target at-risk areas with thermal imaging

The hospital system also hired experts to assess its facilities where remodeling projects may have caused dust- or construction-related risks. For lower-immunity patients, such as in cancer treatment areas, even low levels of microorganisms can cause increased risk. These are certainly areas where basic or fundamental air quality treatment is required.

Other strategies for infection control include:

Administrative controls

Engineering controls

Hand washing


Reduced physical contact

Removal of jewelry

Beyond construction sites, everyday standards of buildings like HVAC systems can play a huge role in spreading HAIs. Improper ventilation, aging equipment, and water damage are all threats to breeding biogenic and environmental contaminants.

Biogenic contaminants include:




Airborne cystic spores

Environmental contaminants include:



Fungi, including mold

In communal areas ventilation plays an important role in maintaining a steady exchange of clean air for potentially contaminated air. These include:

Waiting areas




Maintenance staff must maintain your hospital’s ventilation system for the required air change rate to be sustainable. Clogged filters, leaking ducts, or even contaminated ducts may lead to a buildup of the infectious agents they were designed to remove. Thus, poorly maintained or worn-out ventilation systems may eventually act as a source rather than as a defense against airborne infections.

Ventilation systems must be carefully designed to remove airborne contamination as soon as possible. Filtration systems must have their integrity regularly checked. Laser particle counters  and microbial samplers can provide continuous monitoring of ventilation performance.

At the more personal level, with patients and staff in close proximity, more specific means of personal protection are effective, like masks or a portable air management device.

That said, there are many complex issues surrounding mask wearing. Even though materials, methods, and mask design have improved over the years, there is still variable effectiveness against viral- and bacterial-sized particles.

Other studies have shown the actual act of wearing masks and keeping them on in a proper position is very difficult. Sick patients may have difficulty maintaining proper and consistent mask use — or may be disinterested in doing so — to contain their infection and protect others

What You Need: Airborne Pathogen Reduction Through UV Air Disinfection

HAI Outbreaks in Hospitals Are Preventable

Historically, hospitals don’t regularly test for environmental airborne microbiology, with the exception of surgical suites. Staffers address surface and contact containment as much as possible. New technologies like UV-based surface eradication are certainly helping.

But for some reason, airborne pathogens are typically addressed after the fact. Thankfully, more and more advanced Infection Prevention Programs are calling for proactive measures. 

The goal is to limit liability and expenditures associated with HAIs.

Proactive health care facility managers want to identify potential issues and address them at the source, before they become a crisis. This is possible thanks to portable air disinfection devices.
“With the increase in viral infection and the possibility of pandemics when large numbers of patients will have to be treated and where many others will be at risk of acquiring infections, now is the time to invest in radical new ventilation design and management strategies as well as portable air management devices.”

— Eames, I., et. al. “Airborne Transmission of Disease in Hospitals.” J Royal Society Interface. Dec. 2009. 6: p. 697-702.

UV Air Disinfection Machines

You’ve heard a lot about the horrors of airborne pathogens in hospitals and bogus air disinfection claims. It’s because of this knowledge that we can now finally address how to truly decrease infection rates in hospitals.

There are two basic physical principles of ventilation in infection control:

Diluting airborne pathogens

Controlling airborne pathogen movement from one space to another

That said, you’ll need to consider numerous factors when choosing the appropriate UV air disinfection solution for your specific application and needs. These factors include:

  • Functionality
  • Portability
  • Design
  • Weight
  • Pathogen killing
  • Odor removal
  • Air flow rates
  • Air inflow/outflow sites
  • Safe use
  • Noise level
  • Independent, third-party efficacy testing
  • Verification of efficacy claims for particulate reduction
  • Absence of dangerous byproducts

Even though air disinfection machines don’t have to be registered, the EPA has set guidelines for the appropriate type and size of bioaerosol chamber in which to test them. Products tested under this guidelines have verifiable pathogen-killing efficacy.

Other airborne pathogen efficacy parameters that require assessment include:

An independent, third-party, nationally recognized lab facility

Test methods employed

Contact time (minutes vs. hours)

Type of pathogen

Killing percentage (ideally 99.9995%)

When analyzing and comparing these devices, it’s extremely important that testing parameters are actually directly comparable. The same conditions apply to field studies. The field studies should be conducted at unbiased facilities with scientific test conditions that eliminate all testing room variables except for the air management device itself.