Improved HVAC filtration and disinfection: Bipolar ionization meets one of ASHRAE’s COVID-19 pandemic recommendations

August 6, 2020 by Graboyes Smart Buildings

Research related to the COVID-19 pandemic indicates that densely occupied, poorly ventilated buildings are a significant risk factor in the transmission of viruses including SARS-CoV-2. The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) has developed guidelines on how to operate HVAC systems during the COVID-19 pandemic, and we’re going to discuss one aspect of those recommendations:

Improved air filtration and disinfection and confirmation of its effectiveness

ASHRAE recommends mechanical filter efficiency be at least MERV 13 and preferably MERV 14 or better to help reduce the transmission of infectious aerosols. Because many HVAC systems were designed to operate with MERV 6 to 8 filters, implementing ASHRAE’s recommendation will result in a higher cost of operation due to the greater air pressures required to move air through the filters once the new filters have been installed.  

Bipolar ionization

AtmosAir Solutions, a partner of Graboyes Smart Buildings, manufactures a bipolar ionization (BPI) system. BPI has been tested and found to reduce the levels of various types of airborne contaminants with a MERV equivalent of 13 and without the pressure increase of MERV 13 mechanical filters.  Most recently, its BPI system was tested by Microchem Laboratories against a surrogate for SARS-CoV-2 (because the SARS-CoV-2 virus is not yet available for testing outside of highly controlled laboratories) and was found to reduce the level of the surrogate by 99% after 30 minutes of exposure to the AtmosAir ionization.  AtmosAir cannot claim with 100 percent certainty that its BPI will have similar effectiveness against SARS-CoV-2. However, the molecular structure of the surrogate tested is very similar to SARS-CoV-2.  With use of AtmosAir’s BPI, it is possible to implement ASHRAE’s recommendation while maintaining a similar cost of operation as existed prior to installing more efficient mechanical filters.   

IAQ monitoring, recording, and trending

Many buildings have building automation controls for their heating, ventilation, and air conditioning systems. However, these control systems usually do not monitor levels of particulate and total volatile organic compounds (TVOCs), or the air quality index (AQI) of individual spaces which are indicators of an HVAC system’s filtration effectiveness.  By adding indoor air quality sensors, a facilities team can monitor, record, and trend:

  1. AQI (air quality index)
  2. PM 2.5 (particulate matter 2.5 microns or larger)
  3. TVOCs (total volatile organic compounds)
  4. CO2
  5. Temperature
  6. Humidity

Having this information allows the facilities team to understand IAQ conditions in the space and know when filters and other measures, such as BPI, need to be replaced so their effectiveness can be maintained. 

Cost of implementing AtmosAir Solutions’ BPI system

What might it cost to implement AtmosAir’s BPI system in conjunction with indoor air quality monitoring?  As an example, design and installation of AtmosAir devices in a 25,000 SF building for a 36-month lease would realize a cost of $974 per month including maintenance of the devices.

Graboyes Smart Buildings also has partnered with kaiterra, the manufacturer of the Sensedge IAQ sensor, to provide IAQ monitoring for buildings. We recommend following the WELL Building Standard and installing one Sensedge sensor for every 3,500 SF of occupied space.  For our example of a 25,000 SF building, the monthly lease payment for 36 months would be $665 including maintenance and monitoring of the sensors. 

To learn more contact Ellis Guiles at [email protected] or visit our website at