Measuring PM2.5 and CO2 in schools

Kristina Koh
Published on
Monday, November 8, 2021

For over a year now, Arc Re-Entry has been providing thresholds for those returning to school, work and play. As the pandemic raises concerns for indoor air quality (IAQ), demand for measuring IAQ is growing. Particularly for those who are still developing their lungs and cognition, measurement of carbon dioxide (CO2) and fine particulate matter (PM2.5) is necessary to ensure healthy conditions in schools. That is why Arc Re-Entry has increased its attention to CO2 and PM2.5 and provided new guidance to help schools promote the health and safety of students and faculty. These new resources help schools establish goals for measuring and provide thresholds for their performance. 

Using Arc Re-Entry’s existing platform and PNNL prototype of their primary school building layout, users will learn various strategies to measure CO2 and PM2.5 in their schools. Based on the school’s goals for measuring, we provide best practice to achieve high quality data. With these high quality data, users can develop strategies to maintain or improve their IAQ.


Re-Entry: Guide for CO2 Measurement provides:

  • Information on cognitive health effects of CO2
  • Strategies for measuring average and maximum CO2 levels
  • Strategies for measuring HVAC operating conditions
  • Instructions on sensor placement locations

Re-Entry: Guide for PM2.5 Measurement provides:

  • Information on respiratory health effects of PM2.5 
  • Strategies for measuring for:
    • Mechanically ventilated schools
    • Naturally ventilated schools
  • Strategies for goals such as:
    • Determining internal PM generation or human contribution
    • Determining outdoor PM2.5 pollution infiltration
    • Determining air handler effectiveness

Performance Reports

Projects can input their floor area coverage, temporal coverage, and CO2 or PM2.5 performance data into Arc Re-Entry. Arc Re-Entry provides tools to help facility managers use indoor air quality measurements to inform operations. Every Arc user can collect, manage, and score data through the Re-Entry section under Meters & Surveys. Arc Essentials users can create, download and share customized reports for projects and portfolios.

Access the Guides

Users can download the Arc Re-Entry: Guide to Measuring CO2 and Arc Re-Entry: Guide to Measuring PM2.5 for free from our Guides page.

Access the Education Session

View the original education session on demand, which provides more detail on measuring school IAQ and implementing your re-entry strategies, along with numerous other Arc resources on our video channel. For those seeking Continuing Education (CE) credits, you can access the same course on the USGBC Education platform.


Learn more

The Arc team and our partners welcome the opportunity to share more detailed information about any aspect of measuring CO2 and PM2.5 in schools. Please email questions to