Predictability of the winter haze pollution in Beijing-Tianjin-Hebei region in the context of stringent emission control

Previous studies have demonstrated that seasonal weather forecasting together with the functional relationship between atmospheric circulation indices and the pollution level can facilitate the prediction of haze/air quality in the heavily polluted Beijing-Tianjin-Hebei region (BTH). Air quality is sensitive to pollution emissions, which have been significantly curtailed since 2012 across most of China. This raises the question of the predictability of winter haze pollution in BTH in the context of greatly emission controls. Thus the stability of the relationship between atmospheric circulation and haze pollution in BTH was examined in the study. The results suggest that the winter haze pollution in Beijing and BTH can still be highly predicted by using the atmospheric circulations, despite significant reductions in pollutant emissions and fundamental improvements in air quality in recent years. The high predictability may be attributed mainly to two reasons, namely the physical mechanism of the influence of atmospheric circulation on winter meteorological conditions region and the high amount and intensity of pollutants emission in BTH. The numerical simulations reveal that the probability of air pollution (PAP) may decrease nonlinearly and vary among regions. As the base emissions in 2016 decreased to 50% at a rate of 10%, the PAP moderately decreased from 77.2% to 57.6% in the heavily polluted BTH. It is likely that winter haze events may still occur frequently in BTH when suffering adverse meteorological conditions in the near future. Therefore, a further understanding of the predictability is conducive to prediction and management of air pollution.