downward trend, with a spatial distribution pattern of higher in the north and the east but lower in the south and the west. The exposed population showed a decreasing trend. The overall frequency of PM2.5 concentration decrease was 0.13 μg·m-3/a. The number of PM2.5 – attributable mortality decreased from 86,297 in 2014 to 82,667 in 2021. Ischemic heart disease had the highest number of attributable mortality, with an average of 55,072 deaths per year. Chronic obstructive pulmonary disease and lung cancer had relatively high numbers, while respiratory tract infections were lower, with an average of 4,034 deaths per year.

studied using a flocculation sedimentation experiment. The morphology of flocs was observed by metallographic microscope and scanning electron microscope, and the microscopic adsorption mechanism was studied utilizing density functional theory (DFT). The results show that the best reagent system for the montmorillonite sample is that the molecular weight of NPAM is 14 million and the added amount is 100 g/t. The floc size increases with rising NPAM dosage, forming a unique multi-level compact space network structure through polymer bridging. The adsorption energy of acrylamide on the Na-(001) surface of montmorillonite is -108.81 kJ/mol, which is significantly higher than -50.66 kJ/mol on the None-(001) surface. Hydrogen bonding is not the main reason for the adsorption of acrylamide on the montmorillonite surface. NPAM mainly causes the flocculation and sedimentation of montmorillonite through the processes of polymer bridging and electrostatic attraction. This study can provide a theoretical basis for the design and synthesis of new flocculants.

catalytic properties. In this study, nitrogen atoms were decorated into carbon structure by a unique ultrasonic method, then the nitrogen-doped carbon material was applied as catalyst in CO2 reduction, it exhibited excellent electrochemical activity, 4 times higher than the normal method. The improved activity should be attributed to the interaction between nitrogen and carbon atoms through analysis.

the conversion of lignin model compounds and Indulin AT lignin compared with processes using the mononuclear complexes Zn(salen) and Zn(Phe-TPP). The yields of long and convoluted aromatics from the catalytic oxidation of Indulin AT lignin with ZnPSC6 reached high values after reaction at 80°C for 24 h. Notably, the formation of vanillin was promoted by the increase in active sites over ZnPSC6. This was followed by a significant decrease of β-O-4 linkages and refractory condensed substructures in the lignin, induced by ZnPSC6. This may be expected to be an important area for further study.