Application of a novel second-order differential equation grey model to forecast NOx emissions in China

Nitrogen oxide (NOx) contains two harmful air pollutants: nitric oxide (NO) and nitrogen dioxide (NO₂). The reasonable prediction of China's NOx emissions is of positive significance for the government to formulate environmental protection policies. To this end, a new grey prediction model with second-order differential equation is proposed in this paper, which has more reasonable model structure and better modeling performance than the traditional grey model. Secondly, according to the data characteristics of NOx emissions of China in recent years, a smoothing algorithm and weakening buffer operator are employed to process the original data to solve the rationality of the prediction results of the new model. Thirdly, the model for predicting China's NOx emissions has been constructed by the new proposed model. The results show that the mean comprehensive error of the new model is only 0.0692%, and its performance is much better than that of several other mainstream grey prediction models. Finally, the new model is applied to China's carbon dioxide prediction in the next 5 years, and the rationality of the prediction results is analyzed. Based on the prediction results, relevant countermeasures and suggestions are put forward.