When seeking air purification technology, foodservice operators can choose from several options.
As mentioned, HEPA filters trap 99.97% of particles that are 0.3 microns. Most consist of interlaced glass fibers that create a stringy maze. As particles traverse this web, they’re taken out of circulation by direct impaction, with dust, mold and other contaminants sticking to the filter; sieving, with the airstream carrying a particle until the filter ensnares it; interception, or when particles stick to fiber sides; or diffusion, when fine particles moving more erratically stick to the filter fibers.
Some systems can use activated carbon filters in conjunction with HEPA filters. These systems have larger surface areas and can absorb harmful gases, including VOCs, ozone and radon.
UV lights can kill airborne germs and viruses, but it takes several minutes of sustained exposure to accomplish the task. Ultraviolet light-based systems immerse the HVAC coil in UV light, which kills airborne virus particles as they go through the coils. For UV to be most effective, it needs to saturate a particle for a minimum of 16 seconds. This requires a large HVAC system with enough coil surface to execute such a task in that specific amount of time. For this reason, this method is not ideal for most foodservice operations. Restaurants with multiple HVAC systems dedicated to different areas of the operation, such as the kitchen and various dining zones, typically would be large enough to accommodate a UV-based solution.
UV-C, or germicidal lamps, kill airborne bacteria and viruses and also have been used to sterilize drinking water. This method is common in healthcare settings. Recommended by the FDA and CDC, UV-C light is an accepted and proven technology used for virus, bacteria and mold mitigation.
One air purification technology originally designed to eliminate mold, bacteria and ethylene gas molecules from the walk-in coolers to extend the life of fruits and vegetables has been repurposed for air purification. This virus-killing line pulls air at the rate of 150 cubic feet per minute to one side of the reaction chamber, destroying the virus, bacteria or mold and then exhausting purified air back into the restaurant space. Exposure to the self-contained germicidal UV-C light eliminates airborne contaminants. The circulation and cleaning of air through the unit provides continuous inactivation of the microbial load in the space and reduces the risk of virus transmission.
There is also an air purification system for air curtains that complements the environment’s indoor air quality and disinfection efforts. This system includes the NPBI module, a washable 1-inch-thick aluminum mesh MERV-8 particulate filter and a 10-speed, ½ -hp, electronically commutated motor. When the door is open, the air curtain doubles as an air purifier. It deactivates viruses and kills bacteria and mold spores starting at the entrance and continuing throughout the space.
Air scrubbers with a four-stage filtration process are suitable for foodservice applications during operational hours.
One new technology combines superoxide ions (which electrically charge airborne contaminants and cause them to form clusters, aiding in removal from
the air) with Plasma Quatro, a gas energized by high-intensity UV light, to kill biohazards in the air. It also destroys odors as well as increases the shelf life of perishable products.
PCO Technology uses 254-nm UV-C lights and a catalytic oxidation process to break down and inactivate viruses, bacteria and microorganisms, aiding in their removal from the air.
Purchasing Considerations
When choosing an air purification method, consider additional efficiency measures like air exchanges per hour (ACH) and cubic feet per minute (CFM). Doing so ensures optimal air exchanges for the spaces operators seek to protect.
Use an air quality monitor to perform indoor air quality (IAQ) tests. Structural engineers, mechanical engineers or industrial hygienists can assess IAQ parameters and test and balance HVAC systems for proper IAQ and ventilation. Make sure to follow EPA and OSHA recommendations, including guides for IAQ and best practices for IAQ in commercial settings.
Portable air purifiers offer the benefit of removing fine particles and odors as needed and can do so with low noise levels.
Ionizers, which send out negative ions to attach to air particles, causing them to stick to surfaces such as walls and floors through static electric interactions, are not recommended for restaurant air purification. The negative ions can react with air particles to produce harmful particulates and VOC gases.
