IN-24-C005 - Feasibility of Use of Auto-calibrated CO2 Sensors in Rural Alaskan Homes Through Long-term CO2 Data Analysis

Due to harsh winters and lack of access to resources, many rural Alaskan households experience unusually high energy burdens (5-13%) compounded with overcrowded homes. Further, our prior research suggests that approximately 50% of homes experience mold or moisture concerns. These factors combined suggest a possibility for indoor air quality (IAQ) concerns, however long-term household-level data from this region is sparse. Further data collection and monitoring are thus needed to better benchmark the current state of IAQ in these households. To establish a baseline of IAQ data, a sufficient number of homes’ worth of data collection is needed. It is typically economically unfeasible to use laboratory-grade equipment for long-term field data collection in such rural areas, necessitating the use of lower-cost IAQ sensors including for measuring CO2. However, such sensors often have challenges with long-term drift; some include auto-calibration algorithms to enable the CO2 sensors to self-calibrate, but only when exposed to conditions similar to outdoor air. In order for this to be feasible without intervention, the indoor air that the sensors are calibrated to must reach occasionally CO2 concentrations similar to outdoor air. The goal of this research is thus to evaluate the feasibility of auto-calibration of CO2 sensors in rural Alaskan housing. This is accomplished through long-term CO2 concentration monitoring from May 2023 to February 2024, to determine the CO2 concentration patterns, as well as the frequency at which CO2 concentrations are similar to outdoor levels. Results suggest that indoor air only fell below the required 400 ppm for calibration between 14% and 28% of the weeks surveyed. The mean CO2 concentrations across monitored homes range from 600 to 1440 ppm, and 18% of homes never reached 400 ppm during the monitoring period. This suggests that calibrating the utilized CO2 sensors against low indoor CO2 concentrations is not feasible within Alaska without additional support to ensure accuracy.