Air-tight buildings have become a source of contention as facility managers must weigh energy efficiency versus breathable air. Bringing in more outside air equates to conditioning and cleaning more air, which equates to more energy usage. Then came COVID-19. Now it is not just a matter of cleaner air, but also pathogen-free air. FMs must now consider disinfectant foggers, continuous wiping of surfaces/touchpoints, masks, distancing, UV, HEPA, ionization, ozone, advanced active photocatalytic oxidation (AAPO), activated carbon and even more tools to ensure perceived and actual safety. Vendors came out of the woodwork with technologies and methodologies. FMs suddenly were thrown to the wolves. They must find a way to make it all happen without breaking the bank.

Indoor air quality (IAQ) is still a hot topic, raising several big questions:

  • What is the best technology to accomplish my needs?

  • How do I determine the placement/quantity?

  • How will it affect my carbon footprint?

  • How will it affect my preventive maintenance scheduling?

  • What will the maintenance costs be?

  • Do I want installed equipment or portable?

  • Can filters alone eliminate pathogens?

  • Do I want active or passive devices?

  • Do I want to kill or trap the pathogen?

Active vs. passive

Passive systems only filter what is pulled in by the fan. HEPA, bipolar ionization, activated carbon and ozone generators are passive. Active systems seek pathogens and kill or make them inert wherever they are in the air or on surfaces. UVC and AAPO are both active.

One question at a time:

First though we decide what is the problem with the air? Is it odor? Particulate? Pathogenic? Multiple issues? Determining this answer will determine the type(s) of technology to choose. Once this is determined, FMs can look at potential hazards, ongoing cost and what each solution affects (air-only or air and surfaces).

Hazards:

UVC-254 is unsafe in occupied rooms because the light waves used to kill pathogens also kill human RNA/DNA. This is a great solution for flash disinfecting spaces with high infection rates such as operating rooms, clinics, classrooms and conference rooms when they are emptied.

According to the U.S. EPA, the article “How Does an Air Ionizer Work?” in Healthline as reviewed by Alana Biggers, MD, MPH, bipolar ionization can put unsafe levels of ozone in the air causing short- term throat irritation, chest pain, coughing, shortness of breath and difficulty breathing. Long-term effects could be reduced lung function, worsening asthma, higher risk of respiratory infections and lung inflammation. Independent studies have also shown that bipolar ionizers do not reduce the pathogens at the rates claimed, which has resulted in multiple lawsuits for falsifying claims of efficacy

As for ozone generators, CARB (California Air Resources Board) says: “Some devices that are advertised as air purifiers purposely emit large amounts of ozone, the main component of smog. CARB recommends that ozone generators not be used, except for approved industrial purposes where harmful exposure to ozone is prevented.

Not only are ozone generators ineffective at cleaning indoor air, but inhaling ozone poses serious health risks for humans and animals.”

Ongoing costs

All devices, except for some AAPO devices, have parts such bulbs and filters to replace. The cost of parts must be included with the cost of labor to get the overall cost of IAQ maintenance. FMs must also consider the ongoing cost of electricity. Motors and fans cost money and have wear and tear. Bulbs and AAPO have no moving parts, so will use less electricity.

What each device affects

UVC and AAPO both disinfect air and surfaces; all other types clean only the air. Some, the air that passes through its filter; others, ozone generators and bipolar ionization, the air reached by the ozone.

Additional thought-provoking tidbits

UVC in ductwork would require a minimum of 20 feet of UV light to have enough exposure to kill pathogens at the speed the air is traveling. To avoid turbulence in the duct, that 20 feet of duct would have to be acrylic with the bulbs on the outside. Any pathogens in the duct and its lining would not be affected. Therefore, this would only be cleaning the outside air and any recirculating air.

With UVC light bathing the room, pathogens are being killed as they are exhaled into the air and on surfaces.

HEPA/MERV 13+ will trap the pathogen, but there are three things to consider:

  1. Not all HVAC systems can function with MERV 13+ filters, so this might not even be an option.

  2. The tighter the filter medium the more frequently it will need to be changed due to more particulate being trapped faster.

  3. Pathogens could be trapped only and released back into the air upon filter removal due to shaking and movement. This does require that the pathogen be pulled into the filter by a fan.

HVAC systems will exchange the air in a building 6-12 times per hour depending on design. A typical fan type device (activated carbon, HEPA) will clean, depending on the fan speed, a median of 1,000 cubic feet in an hour. If HVAC is replacing the air up to 12 times in an hour, how will a fan-type device ever clean all the air in the room?

Activated carbon can kill pathogens, but the points regarding HEPA/MERV13+ apply.

AAPO will actively kill pathogens in the air and on surfaces, not just those pulled into a filter. Some AAPO devices that have added a fan and filtration in the portable units.

There are dozens of independent studies showing the efficacy of AAPO as a first-installed device, demonstrating it is more effective than other devices. These studies were done in buildings with one type of device installed, samples of air and surfaces taken for a virus count; then AAPO installed, run, and samples taken of the same surface and air locations. The results showed more than a 60 percent reduction in pathogen saturation.

Review

Many electronic air cleaning technologies are not evaluated by federal agencies or industry standard organizations for their efficacy or for potential unintended consequences, including the generation of hazardous chemical byproducts.

Even fewer technologies have independent studies, and most only have what the manufacturer has determined.

Only one technology has dozens of independent studies regarding efficacy, and comparisons in live buildings of active technologies.

Crucial to maximizing the efficiency of any in-room air cleaner (passive) is its strategic placement and setup within a room, which should be done in consultation with ventilation engineers, infection control experts and/or industrial hygienists. A poorly positioned air cleaner may disrupt air-flow patterns within the room and through the air cleaner, thereby compromising its air cleaning efficiency.

All this considered, it is important to remember:

  • One size fits all does not apply to IAQ. The needs and objectives of each organization and space within each building can require different solutions.

  • Do you want to make a decision, or make a difference?

Do your due diligence to make a difference.