[Simulation of the Spatio-temporally Resolved PM Aerosol Mass Concentration over the Inland Plain of the Beijing-Tianjin-Hebei Region].

In recent years, haze pollution in China is becoming increasingly serious, especially in the Beijing-Tianjin-Hebei region. In order to identify the temporal and spatial distributional characteristics of PM aerosol mass concentration in the region, this study selected the inland plain of the Beijing-Tianjin-Hebei region as the research area, and used MODIS AOD as the main predictor in a mixed effects model to establish the daily relationship of AOD-PM in the study area, from 2013 to 2014. The model was validated by a ten-fold cross validation method. The results showed that the correlation between AOD-PM can be improved by daily calibration of the mixed effects model (=0.78); the cross-validated was 0.70, and RMSE and RPE were 20.80 μg·m and 28.76%, respectively. Considering the importance of unbiased PM predictions, the correction factors calculated from the surface PM measurements were applied to correct the biases in the predicted annual average PM concentrations introduced by non-stochastic missing AOD measurements. The results showed that the annual average concentration of PM in the study area was higher than 75 μg·m, and the spatial distribution of PM concentration was higher in the southern and western regions, and lower in the northern and eastern regions. These results suggest that the mixed effects model can be used to monitor ground PM, and also provide a scientific basis for the control of atmospheric particulate pollution in the region.