Scientific Reports (Dec 2020)

Spatial calibration and PM2.5 mapping of low-cost air quality sensors

  • Hone-Jay Chu,
  • Muhammad Zeeshan Ali,
  • Yu-Chen He

DOI
https://doi.org/10.1038/s41598-020-79064-w
Journal volume & issue
Vol. 10, no. 1
pp. 1 – 11

Abstract

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Abstract The data quality of low-cost sensors has received considerable attention and has also led to PM2.5 warnings. However, the calibration of low-cost sensor measurements in an environment with high relative humidity is critical. This study proposes an efficient calibration and mapping approach based on real-time spatial model. The study carried out spatial calibration, which automatically collected measurements of low-cost sensors and the regulatory stations, and investigated the spatial varying pattern of the calibrated low-cost sensor data. The low-cost PM2.5 sensors are spatially calibrated based on reference-grade measurements at regulatory stations. Results showed that the proposed spatial regression approach can explain the variability of the biases from the low-cost sensors with an R-square value of 0.94. The spatial calibration and mapping algorithm can improve the bias and decrease to 39% of the RMSE when compared to the nonspatial calibration model. This spatial calibration and real-time mapping approach provide a useful way for local communities and governmental agencies to adjust the consistency of the sensor network for improved air quality monitoring and assessment.