Reliability and performance of real-time gas sensors for continuous monitoring of indoor TVOC concentrations

We studied reliability and performance of four metal oxide semiconductor sensors and one photo ionization detection sensor in continuous monitoring of volatile organic compounds (VOCs) in laboratory and field experiments. In the laboratory experiments, we examined responses of the sensors using zero and isobutylene gases. In the field experiment, we monitored indoor air TVOC concentration continuously for eight-day period in a classroom of a high school building. We used active sampling of indoor air on Tenax TA sorbents and analysis of samples with gas chromatography as a reference method. In the laboratory experiments, all tested sensors showed the lowest values of their measuring range for the zero gas, but variation between different sensors occurred in the isobutylene gas experiment. In the field experiment, TVOC concentrations measured with the sensors were significantly higher compared to the reference method. Our results suggest that real-time gas sensors are not suitable for monitoring absolute TVOC concentrations. However, it is possible to use them to detect and understand temporal changes in indoor air quality. © 2020 16th Conference of the International Society of Indoor Air Quality and Climate: Creative and Smart Solutions for Better Built Environments, Indoor Air 2020. All rights reserved.