Performance of Low-cost PurpleAir Sensor in Monitoring Indoor Aerosols
SHINHYE LEE, Donghyun Rim, Myoungsouk Yeo,
Architectural Engineering, Seoul National University Abstract Number: 561
Working Group: Indoor Aerosols
AbstractIndoor aerosol concentrations can be occasionally higher than outdoors which brings attention to the importance of monitoring indoor particle concentrations. Optical light scattering low-cost monitors such as PurpleAir are being increasingly used because of short-term, real-time measurement capability at an affordable price in ordinary households. However, limited information is available for PurpleAir regarding measuring common indoor aerosols, compare to ambient air. The objective of this study is to evaluable performance and reliability of PurpleAir in aerosol monitoring in residential environments. Performances of PurpleAir and three research-grade optical particle monitors (Grimm 11-D, Aerotrak 9306, Sidepak AM520) are evaluable in a laboratory chamber and a full-scale apartment with common indoor emission sources such as incense stick burning and bacon pan frying. The results show that PurpleAir has high intra-model consistency and high linearity for mass concentrations (e.g. PM2.5) that are comparable to the research-grade sensors for all size bins, although differences in mass concentrations between the PurpleAir and other monitors are observed with concentration level. With regards to measuring number concentration (particle counts), the intra-model consistency was much lower than mass concentration, especially for particles larger than 5μm. Furthermore, the linear regression slopes between PurpleAir and research-grade monitors varied notably with the emission sources. This discrepancy between mass and number concentration measurements are likely attributed to the PurpleAir algorithm that constrains the number fraction of each size bins. These results suggest that performance of PurpleAir monitor is acceptable for monitoring mass concentrations (e.g. PM1, PM2.5, and PM10); however, measurements of number concentrations are not reliable for analyzing size-resolved indoor particle concentrations.