Investigating emission uncertainties at city level over East China

East China, including the Yangtze River Delta area, hosts the economic engine and many major cities of China. During the past two decades, the rapid economic growth has resulted in significant elevated surface air pollutants over East China. Although modeling skills of air pollutants over East China have been improved, there are still large biases in simulating spatial and temporal variation of surface concentrations of pollutants over the region. The state-of-the-art model WRF-Chem has been widely used for studying air pollutants and their meteorological and climatic feedbacks over East China, however, the model skills in simulating pollutants have not been fully investigated over the region. In the study, the WRF-Chem simulations are conducted over East China for four seasons of 2015. The simulated results are compared with surface observations in several major cities and satellite retrievals over the region. The temporal and spatial variabilities of anthropogenic emissions are found critical in simulating diurnal cycle of surface pollutants at the urban scales. The sensitivity simulations by adjusting spatial and temporal variabilities of anthropogenic emissions can better capture the observed features, indicating more efforts are still needed to reduce the uncertainties of anthropogenic emissions at urban scales in order to reasonably simulate air pollutants over East China.