Performance assessment of low-cost environmental monitors and single sensors under variable indoor air quality and thermal conditions

Recent technological advancements have enabled the development and deployment of low-cost consumer grade monitors for ubiquitous and time-resolved indoor air quality monitoring. With their reliable performance, this technology could be instrumental in enhancing automatic controls and human decision making. We conducted a comprehensive performance evaluation of eight consumer grade multi-parameter monitors and eight single parameter sensors in detecting particulate matter, carbon dioxide, total volatile organic compounds, dry-bulb air temperature, and relative humidity. In the controlled chamber, we generated eight air pollution sources, each at two thermodynamic conditions - cool and dry (20 +/- 1 degrees C, 30 +/- 5%), and warm and humid (26 +/- 1 degrees C, 70 +/- 5%). The majority of tested devices under-reported reference particle measurements by up to 50%, provided acceptable responses for carbon dioxide within 15% and diverging results with poor quantitative agreement for total volatile organic compounds. Despite the reported disparities in quantitative agreements, most of the low-cost devices could detect source events and were strongly correlated with the reference data, suggesting that these units could be suitable for measurement-based indoor air quality management. Most of the tested devices have also proven to competently measure air temperature (within+/-0.6 degrees C) and relative humidity (within+/-5% RH) and maintained a stable measurement accuracy over the two thermodynamic conditions.

Automated summary

The study evaluated the performance of consumer grade monitors and sensors in detecting indoor air pollutants, finding that most devices underreported particulate matter levels, had acceptable responses for carbon dioxide, and diverging results for volatile organic compounds. However, despite the quantitative disparities, the devices were still deemed suitable for indoor air quality management.