Classification prediction model of indoor PM2.5 concentration using CatBoost algorithm

It is increasingly important to create a healthier indoor environment for office buildings. Accurate and reliable prediction of PM_2.5 concentration can effectively alleviate the delay problem of indoor air quality control system. The rapid development of machine learning has provided a research basis for the indoor air quality system to control the PM_2.5 concentration. One approach is to introduce the CatBoost algorithm based on rank lifting training into the classification and prediction of indoor PM_2.5 concentration. Using actual monitoring data from office building, we consider previous indoor PM_2.5 concentration, indoor temperature, relative humidity, CO₂ concentration, and illumination as input variables, with the output indicating whether indoor PM_2.5 concentration exceeds 25 μg/m³. Based on the CatBoost algorithm, we construct an intelligent classification prediction model for indoor PM_2.5 concentration. The model is evaluated using actual data and compared with the multilayer perceptron (MLP), gradientboosting decision tree (GBDT), logistic regression (LR), decision tree (DT), and k-nearest neighbors (KNN) models. The CatBoost algorithm demonstrates outstanding predictive performance, achieving an impressive area under the ROC curve (AUC) of 0.949 after hyperparameters optimition. Furthermore, when considering the five input variables, the feature importance is ranked as follows: previous indoor PM_2.5 concentration, relative humidity, CO₂, indoor temperature, and illuminance. Through verification, the prediction model based on CatBoost algorithm can accurately predict the indoor PM_2.5 concentration level. The model can be used to predict whether the indoor concentration of PM_2.5 exceeds the standard in advance and guide the air quality control system to regulate.