Machine learning methods to predict particulate matter PM2.5

Abstract

<ns4:p>Introduction</ns4:p> <ns4:p> Pollution of air in urban cities across the world has been steadily increasing in recent years. An increasing trend in particulate matter, PM <ns4:sub>2.5</ns4:sub> , is a threat because it can lead to uncontrollable consequences like worsening of asthma and cardiovascular disease. The metric used to measure air quality is the air pollutant index (API). In Malaysia, machine learning (ML) techniques for PM <ns4:sub>2.5</ns4:sub> have received less attention as the concentration is on predicting other air pollutants. To fill the research gap, this study focuses on correctly predicting PM <ns4:sub>2.5</ns4:sub> concentrations in the smart cities of Malaysia by comparing supervised ML techniques, which helps to mitigate its adverse effects. </ns4:p> <ns4:p>Methods</ns4:p> <ns4:p> In this paper, ML models for forecasting PM <ns4:sub>2.5</ns4:sub> concentrations were investigated on Malaysian air quality data sets from 2017 to 2018. The dataset was preprocessed by data cleaning and a normalization process. Next, it was reduced into an informative dataset with location and time factors in the feature extraction process. The dataset was fed into three supervised ML classifiers, which include random forest (RF), artificial neural network (ANN) and long short-term memory (LSTM). Finally, their output was evaluated using the confusion matrix and compared to identify the best model for the accurate prediction of PM <ns4:sub>2.5</ns4:sub> . </ns4:p> <ns4:p>Results</ns4:p> <ns4:p> Overall, the experimental result shows an accuracy of 97.7% was obtained by the RF model in comparison with the accuracy of ANN (61.14%) and LSTM (61.77%) in predicting PM <ns4:sub>2.5</ns4:sub> . </ns4:p> <ns4:p>Discussion</ns4:p> <ns4:p>RF performed well when compared with ANN and LSTM for the given data with minimum features. RF was able to reach good accuracy as the model learns from the random samples by using decision tree with the maximum vote on the predictions.</ns4:p>

Topics & Concepts