It is of great significance to explore the spatial-temporal variations and estimate the relative importance of the influencing factors of PM 2.5 and O 3 pollution. The study established nationwide surface O 3 , NO 2 , and SO 2 estimation models using the extreme gradient boosting model and the data fusion method. The cross-validation results indicated that the forecasted models performed well (R-values from 0.86 to 0.95). The results revealed that the pollution levels of O 3 , PM 2.5 , NO 2 , and SO 2 in the North China Plain (NCP) were the highest in China. Subsequently, a multi-task learning model was utilized to estimate the relative importance of influential factors on the PM 2.5 and O 3 pollution in the NCP. The sensitivity analysis results indicated that the O 3 pollution from 2010-2020 in the NCP was susceptible to meteorological factors such as ultraviolet radiation and temperature, as well as anthropogenic precursors such as NO X , and PM 2.5 pollution in the NCP was constrained by both meteorological factors (44.62%) and anthropogenic emissions (16.86%). The impact of NO 2 on PM 2.5 pollution was similar to its impact on O 3 pollution; therefore, the importance of NO 2 emission reduction to PM 2.5 pollution is as important as that of O 3 pollution, whereas the impact of SO 2 on PM 2.5 was much greater than its impact on O 3 pollution, so SO 2 emission reduction is more important for PM 2.5 .