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Indoor Carbon Dioxide Metric Analysis Tool



Andrew K. Persily, Brian Polidoro


Indoor carbon dioxide has been used for decades to evaluate indoor air quality (IAQ) and ventilation. However, many applications of CO2 as an indicator or metric of IAQ or ventilation reflect a lack of understanding of the relationship between indoor CO2, ventilation rates and IAQ. Often a single CO2 concentration is used as a metric for all spaces, ignoring important differences between spaces, including their occupancy and ventilation requirements. Use of CO2 as an IAQ metric also ignores important indoor air contaminants that are unrelated to occupancy. An approach has been developed to derive CO2 levels that can serve as indicators of outdoor ventilation by estimating the expected concentration based on the intended ventilation rate, the number of occupants and the rate at which they generate CO2. This paper describes an online tool QICO2 that has been developed to perform these calculations.
Proceedings Title
Indoor Air 2022
Conference Dates
June 12-16, 2022
Conference Location
Kuopio, FI
Conference Title
Indoor Air 2022, 17th International Conference of the International Society of Indoor Air Quality & Climate


CO2 concentrations, IAQ metric, online calculator, ventilation


Persily, A. and Polidoro, B. (2022), Indoor Carbon Dioxide Metric Analysis Tool, Indoor Air 2022, Kuopio, FI, [online], (Accessed April 20, 2024)
Created June 14, 2022, Updated November 29, 2022