Validation of linear, nonlinear, and hybrid models for predicting particulate matter concentration in Tehran, Iran

Abstract

Information on particulate matter forecast is significant as it allows residents to manage its undesirable effects. For the purpose of predicting PM10 concentration in the air of Tehran, various models were used, including (i) a linear model (multiple liner regression, MLR), (ii) two hybrid models (Adaptive Neuro-Fuzzy Inference System, ANFIS as well as ensemble empirical mode decomposition and general regression neural network, EEMD-GRNN), and (iii) a nonlinear model (multi-layer perceptron, MLP). The output variable in these models was the measure of suspended particles of PM10 while the predictor variables were the information on air quality which consisted of CO, NO2, O3, PM10 of the previous day, PM2.5, and SO2 as well as meteorological data which included average atmospheric pressure (AP), average maximum temperature (Max T), average minimum temperature (Min T), daily relative humidity level of the air (RH), daily total precipitation (TP), and daily wind speed (WS) for the year 2016 in Tehran. Analysis of the data revealed that in comparison with the results of MLR and MLP, ANFIS obtained the most accurate output (R2 = 0.97, root mean square error (RMSE) = 1.0713, and mean absolute error (MAE) = 0.6111) for the training phase and (R2 = 0.89, RMSE = 3.6165, and MAE = 2.8993) the testing phase. However, the hybrid models which were used in the current study had almost similar prediction results. As it can be concluded, in comparison with linear and nonlinear models, hybrid models turn out to have higher accuracy in predicting PM10 concentration.