The accuracy of a sensor is crucial, and one way to measure this is through its average error. Parameters like Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) help quantify sensor performance. RMSE is stricter than MAE, as it is more sensitive to outliers. The normalized RMSE (nRMSE) is useful for comparing sensor performance in different environments. Interestingly, even reference-grade instruments have uncertainties, with deviations up to 30% being considered acceptable. Overall, low-cost sensors have their advantages, such as easy setup and maintenance, but may have slightly lower accuracy. The US-EPA guidelines help in characterizing sensor accuracy for PM2.5 measurements.
https://www.airgradient.com/blog/how-to-determine-error-of-sensor/