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Final Program


Final Program

ACE 2025

AQMM

Air Sensor Applications

Influence of Home Occupant Activities on Indoor PM2.5 Concentrations

Thursday, June 12, 2025
2:40pm – 3:00pm ET
Location: 302A
Indoor air quality (IAQ) is a critical yet often overlooked aspect of environmental health, influenced by occupant activities and outdoor air infiltration. This study examines the impact of home occupant activities on indoor PM₂.₅ and CO₂ concentrations, as well as seasonal variations in indoor-outdoor PM₂.₅ ratios. Indoor and outdoor air quality was monitored in homes across Houghton and Baraga Counties, Michigan, during the summer and fall of 2024 using low-cost sensors. Results indicate that indoor PM₂.₅ concentrations remained stable during passive activities such as sleeping and resting but increased significantly during cooking, dusting, candle burning, smoking, and wood burning. The indoor-outdoor PM₂.₅ concentration ratio (I/O) varied seasonally, with an average of 1.13 ± 0.34 in Houghton and 3.23 ± 4.55 in Baraga during summer, increasing to 2.84 ± 0.91 and 4.02 ± 3.69 in fall, respectively. The higher I/O ratios in the fall were likely due to a shift from natural ventilation in the summer to mechanical ventilation and indoor wood burning for heating in the fall. Additionally, Baraga homes exhibited higher indoor PM₂.₅ levels, potentially due to proximity to emission sources and differences in occupant activities. These findings highlight the significant role of human behavior and ventilation strategies in indoor air pollution and emphasize the need for targeted mitigation strategies to improve IAQ.