Practical Particulate Matter Sensing and Accurate Calibration System Using Low-Cost Commercial Sensors

Abstract

Air pollution is a social problem, because the harmful suspended materials can cause diseases and deaths to humans. Specifically, particulate matters (PM), a form of air pollution, can contribute to cardiovascular morbidity and lung diseases. Nowadays, humans are exposed to PM pollution everywhere because it occurs in both indoor and outdoor environments. To purify or ventilate polluted air, one need to accurately monitor the ambient air quality. Therefore, this study proposed a practical particulate matter sensing and accurate calibration system using low-cost commercial sensors. The proposed system basically uses noisy and inaccurate PM sensors to measure the ambient air pollution. This paper mainly deals with three types of error caused in the light scattering method: short-term noise, part-to-part variation, and temperature and humidity interferences. We propose a simple short-term noise reduction method to correct measurement errors, an auto-fitting calibration for part-to-part repeatability to pinpoint the baseline of the signal that affects the performance of the system, and a temperature and humidity compensation method. This paper also contains the experiment setup and performance evaluation to prove the superiority of the proposed methods. Based on the evaluation of the performance of the proposed system, part-to-part repeatability was less than 2 μg/m3 and the standard deviation was approximately 1.1 μg/m3 in the air. When the proposed approaches are used for other optical sensors, it can result in better performance.

Drive-by Air Pollution Sensing Systems: Challenges and Future Directions

“…Optical PM sensors are popular due to their low power consumption, low cost, and quick response [52]. However, the sensor's accuracy can be affected by non-target particles (creating noise), interference from ambient sources, reliability of the parts used, and factors affecting the airflow [54]. Furthermore, low-cost PM sensors performance can be affected under conditions of high relative humidity [55].…”

Low-processing data enrichment and calibration for PM2.5 low-cost sensors

“…However, the light scattering method is sensitive to external environment and in particular, to meteorological conditions (especially to temperature, humidity). This can lead to accuracy and stability drawbacks [6][7][8][9]. For instance, PM low-cost sensors often report PM concentration increasing in presence of water droplets in humid meteorological conditions.…”

Design Optimization of a Capacitive Sensor for Mass Measurement of Nanometer-Sized Exhaust Carbon Particles

“…To measure PM2.5 and PM10, an air pollution monitoring device with a particle matter sensor was used [25]. A study which investigated low-cost PM sensors proposed methods to correct the error factors caused by the optical scattering method [26]. A piezoelectric resonating membrane operates the gravimetric-based particulate matter sensor for portable applications, and future work includes implementing a thermophoresis mechanism to remove residual particles deposited on the sensor during measurements [27].…”