Aiming at the problems of large power consumption, poor anti-interference ability, low stability and insufficient prediction accuracy of AQI (air quality index) of traditional air quality monitoring system, an air quality monitoring system integrating low-power wide-area IoT LPWAN, One-NET cloud platform and gated recurrent unit was designed. The system adopted a hybrid mode power supply based on photovoltaics and supplemented by mains power. Long-distance radio LoRa technology was used to collect environmental parameters, and the cloud platform technology and SSA-VMD-GRU (sparrow search algorithm-variational mode decomposition-GRU) coupling model were integrated to realize remote monitoring and prediction of AQI index. Through the communication test, the results showed that within the communication distance of 1 000 meters, the communication rate was above 96%, and the packet loss rate was not more than 4%. The results showed that the SSA-VMD-GRU model had a better prediction effect on AQI index than the traditional GRU model and VMD-GRU model, the root mean square error decreased by 22.434 and 0.833, the mean absolute error decreased by 16.849 and 0.623, respectively, and the prediction error rate was within 3%. The system can realize real-time monitoring of air quality and accurate prediction of AQI index, providing reference for accurate issuance of air quality warnings.