Multitask Air-Quality Prediction Based on LSTM-Autoencoder Model

With the development of the data-driven modeling techniques, using the neural network to simulate the transport process of atmospheric pollutants and constructing PM_2.5 time-series prediction model have become a hot topic. The existing data-driven approaches often ignore the dynamical relationships among multiple sites in urban areas, which results in nonideal prediction accuracy. In response to this problem, this article proposes a long short-term memory (LSTM) autoencoder multitask learning model to predict PM_2.5 time series in multiple locations city wide. The model could implicitly and automatically excavate the intrinsic relevance among the pollutants in different stations. And the meteorological information from the monitoring stations is fully utilized, which is beneficial for the performance of the proposed model. Specifically, multilayer LSTM networks can simulate the spatiotemporal characteristics of urban air pollution particles. And using the stacked autoencoder to encode the key evolution pattern of urban meteorological systems could provide important auxiliary information for PM_2.5 time-series prediction. In addition, multitask learning could automatically discover the dynamical relationship between multiple key pollution time series and solve the problem of insufficient use of multisite information in the modeling process of the traditional data-driven methods. The simulation results of PM_2.5 prediction in Beijing indicate the effectiveness of the proposed method.

I. Introduction

With the development of industry and economy, the emission of various kinds of pollution gas and solid particle suspension increases year by year, which causes serious air pollution problems in many countries. China is the biggest developing country and the air pollution issue has become the concern among citizens [1]–[3]. In January 2017, haze in Beijing lasted for 26 days. Meanwhile, less than 1% of China’s 500 largest cities reached the air-quality standards recommended by the World Health Organization. Therefore, air-quality prediction in city-wide area has been an important public concern.