Evaluation of low-cost particulate matter sensors OPC N2 and PM Nova for aerosol monitoring

Abstract

Low-cost sensors have the potential to revolutionize air pollution research by providing high spatial resolution data. However, data accuracy from the low-cost sensors remains a major concern. Therefore, it is necessary to evaluate the performance of the low-cost sensors. The current study evaluated the performance of two such low cost PM (particulate matter) sensors viz. OPC N2 (∼400 USD) and PM Nova sensor (∼20 USD) for four different uncontrolled test environments i.e. (a) Indoor (b) Indoor with incense stick (c) Ambient air (outdoor) and (d) Traffic, using an aerosol spectrometer (GRIMM 1.108) as the reference instrument. The results showed that both OPC N2 and PM Nova can record the airborne PM concentration with good accuracy as demonstrated through linear regression with Grimm (OPC N2, R2 = 0.954–0.987 and PM Nova, R2 = 0.872–0.981). The performance of the sensors was better for the finer particles (PM1 and PM2.5) than coarser particles (PM10). Meteorological parameters such as wind speed, temperature and RH did not have any significant impact on the sensor performance. Using a sampling tube did not have an impact on sensor performance. A modified python script for data retrieval from the sensors in a user-friendly format has been developed. More evaluations of used sensors and in diverse environmental settings can further increase the understanding about the sensor performance.