Indoor Air Quality Assessment

The College of New Jersey (TCNJ) Ewing, NJ



Higher education has been dramatically impacted by the COVID-19 Pandemic. Facility managers are challenged with optimizing the operational performance of their buildings to the greatest extent possible in concert with behavioral changes (i.e., masks, social distancing, and cleaning) to minimize the risk to occupants. In an effort to create the safest environment possible for students to return to in-person instruction, TCNJ engaged Entech to assess and analyze the Indoor Air Quality (IAQ)of multiple locations on campus to determine current conditions and provide recommendations for optimization.

We modeled and analyzed operational and mechanical options to reduce individual and community transmission risks. The resulting recommendations were reviewed with TCNJ and we assisted with the implementation of selected options.

Solution Details

We utilized the Airborne Infection Risk Calculator (AIRC)*. This tool was developed by researchers in the Building Performance Lab at the City University of New York (CUNY). The contagion model is designed to assist with evaluating individual infection and community transmission risks associated with specific indoor environments.

We applied the calculator to a variety of spaces on campus, including a COVID-19 Rapid Testing Site for students, academic spaces including classroom and lab spaces, a performance theatre, athletic facilities and campus television and radio studios.

The AIRC addresses two primary questions related to the risks associated with occupying an indoor space when community transmission of an infectious airborne pathogen (such as SARS-CoV-2) is occurring:

  • What is the potential infection risk associated with lengths of stay in the space?
  • What occupancy rate helps prevent exposure from further contributing to disease spread?

For each space, a baseline is created using information related to each space’s intended occupancy and current HVAC system characteristics. Once a baseline is established, iterations can be created by modifying inputs to represent changes to the space (i.e., added filtration systems, occupants spending shorter periods of time in the room, etc.)

Based on information garnered from AIRC, along with IAQ industry standards and various ASHRAE epidemic guidelines, space-specific mitigation recommendations included:

  • Use of surgical masks or N95 respirators
  • Enhanced FIltration
  • Speech amplification to reduce loud speech
  • Use larger rooms for discussion
  • More outside air per occupancy
  • Reduce occupancy limits
  • Provide breaks between classes
  • High air change rate and good air mixing
  • Limit recirculation within space (or MERV 13+ filtration for all recirculated air)
  • Utilize HEPA filter plug-ins where feasible

While recognizing that no in-person activities can occur without some risk of transmission of SARS CoV-2, the AIRC model indicated that by implementing recommendations along with behavioral changes, there would be a less than 1% probability of infection transmission in the areas evaluated*. This will provide TCNJ with the best possible indoor air quality during the Pandemic and beyond.

Although the AIRC cannot guarantee that infections will not occur, it was a powerful tool in helping TCNJ to understand the risks, compare the effectiveness of options, and help make more informed decisions for their indoor spaces. These steps demonstrate their commitment to the safety of their students and staff.

*Disclaimer: The AIRC outputs of modeled statistical risk of airborne infection based on a set of space-specific inputs should not be construed as an accurate predictor of infection rates. Significantly different results might occur in real life.

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<1% modeled risk of infection

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